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Credit: Bryce Vickmark
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In footnotes or endnotes please cite AIP interviews like this:
Interview of Nergis Mavalvala by David Zierler on February 18 and April 26, 2021,
Niels Bohr Library & Archives, American Institute of Physics,
College Park, MD USA,
For multiple citations, "AIP" is the preferred abbreviation for the location.
Interview with Nergis Mavalvala, Kathleen and Curtis Marble Professor of Physics and Dean of the School of Science at MIT. Mavalvala surveys her administrative focus as Dean in a time of the pandemic, and to foster inter-departmental research. Mavalvala recounts her childhood in Karachi, Pakistan, and her Zoroastrian heritage, and she explains the opportunities that led to her coming to the United States where she pursued her undergraduate education at Wellesley and she developed her skills in experimental physics and in the machine shop. She describes her decision to attend MIT for graduate school, and she narrates meeting Rai Weiss and her involvement in the LIGO project. Mavalvala describes coming to understand her queer identity in graduate school and her understanding of the complex arrangement between Caltech, NSF, MIT and the detector sites in Washington state and Louisiana. She discusses her postdoctoral position with the LIGO group at Caltech and her focus on mirror interferometry and Caltech’s support in securing her green card. She explains her decision to return to MIT to join the faculty and the transition to Advanced LIGO. Mavalvala narrates the excitement and moment of LIGO’s detection of gravitational waves, and she explains what it means to detect them and the broader technical, theoretical and astrophysical significance of this achievement. She describes the careful analysis to confirm that data and the excitement surrounding the announcement, and she discusses the generosity in the way that Kip Thorne, Barry Barish, and Rai Weiss accepted the Nobel Prize. Mavalvala emphasizes all of the applied scientific discovery achieved through the creation of the LIGO instrumentation, and she talks about her work as a professor and mentor to graduate students. She explains her decision in accepting the dean position and how she maintained an active research agenda. At the end of the interview, Mavalvala describes all of the fundamental discovery that can be made as the LIGO collaboration charts its future.
OK, this is David Zierler, oral historian for the American Institute of Physics. It is February 18th, 2021. It’s my great honor to be here with Doctor, Dean, and Professor Nergis Mavalvala. Nergis, it’s great to see you. Thank you so much for joining me.
Thank you, David.
To start, would you please tell me your titles and institutional affiliations? And you’ll notice I pluralized everything because I know you certainly have more than one.
[laugh] Yeah, so I’m Nergis Mavalvala, and I’m officially the Kathleen and Curtis Marble Professor of Physics at MIT, and my most recent role is also as Dean of the School of Science at MIT. So, that’s me.
So, to start, who were or is Curtis and Kathleen Marble, and do the Marbles have any connection to your work and what you do?
Yeah, so, that’s a wonderful question. Curt Marble is an MIT alum, who has been very supportive of the physics department at MIT, and actually also biology. And, you know, we’ve become good friends. His wife, Kathy, died a couple of years ago, so we miss her greatly. But I feel some great honor in carrying her name and his in my title because they’ve been, you know, super, super supportive and, you know, a friendship has grown out of the connection. So, yes, I know—I knew them both. I know Curt still, and it’s one of the—one of these professional relationships that just you wouldn’t predict form but it did.
Before we go all the way back to the beginning, and develop your personal narrative, I want to ask a few sort of in-the-moment questions. And the first is, when you were named dean last year, I’m sure, like every great physicist, you were committed to maintaining the science, to continuing with your research agenda. To what extent have you been able to do that, and to what extent has that been fantastical because of all of your new responsibilities?
I think that the answer is evolving. So, certainly, I would say the first—you know, I’m sort of roughly six months into being dean, and the first three were a total and complete blur. I was learning new things, meeting new people, just figuring out “What does a dean even do?”
And that was—you know, so that’s been a bit of a blur. And, in that time, you know, I would say the—my attention to my research group diminished. I think I’m starting to come out the other side now. I think the dean’s job is—has—I’ve found a cadence at which I can do both things. For example, this morning, I had the pleasure of editing a paper that’s coming out from our group. So, I do manage to find a little bit of time to do both—well, a lot of time to do Dean-ing, and some time to do research as well.
Nergis, the timing is so interesting because you stepped into the dean role at a time when, you know, in February or March of last year, we were all operating under the hopeful assumption, maybe the pandemic would be rather temporary. Maybe we’d be able to get back to life as normal. By the summer, obviously, that wasn’t the case. So, you went into this position, I’m sure, with eyes wide open that there would be strategic and structural challenges that no other dean of science at MIT had ever faced. And so my question is, to what extent were you prepared for these challenges going in, and to what extent were you not because some of the things you could only learn on the job as these things were happening in real time?
I would say nobody, even someone who’s been, you know, a masterful administrator or statesperson for a decade, could be prepared for what the pandemic brought. So, in that sense, I don’t feel particularly disadvantaged [laugh]. I thought about this quite a bit as I was, you know, considering whether to step into the role.
And I came to see the events of 2020 —a global pandemic, the rise certainly in the United States for, you know, for a real call for racial justice, the climate crisis, I came to see all of those things in the end as really opportunities for MIT and the School of Science to evolve into something better than we are. And so I set myself a few goals as dean. The single most important goal I set for myself as dean is I’ve inherited a really great School of Science. I’d better not break anything.
So, the first rule is don’t break anything.
But, beyond that, I also see many opportunities for improvement. So, to answer your question, the pandemic has been both a challenge but also I think an opportunity.
One of the great narratives of the School of Science at MIT is the ways in which there is interdepartmental collaboration. So many of the exciting things that are happening at MIT in biomedicine, in AI, in robotics, in quantum computing, in energy and climate change, you see at MIT perhaps more than any other institution that you have departments and professors who are working across traditional divides. Because the pandemic has mandated social isolation, physical isolation, in what ways has this narrative been challenged, and in what ways has the mandate of just being by oneself allowed for collaborations over Zoom that might not have happened otherwise?
So, I’ll tell you my sense and what I hear from my colleagues and the department heads that I work with is that the ability to interact over Zoom has widened the participation. So, people can come to a meeting or a colloquium or a seminar in much larger numbers than we were seeing in person, and this has been sustained through the pandemic. So, you know, I worried about, well, eventually, you know, Zoom fatigue will set in. But people really are showing up. And, so, I would say in terms of some of these activities of academia, I think that’s going pretty well.
In terms of actual, you know, in-the-lab collaborations, I think it’s been pretty hard, right, because social distancing requires if labs are open, you know, it would have to be at very low occupancy. I’ll give you a great example. In one of the labs where one of my graduate students does his experiment, based on the ventilation capacity, I have a quota of one hour per every 24 where I can be in the lab with him. So, for two people to be there with the rate of ventilation we have, that’s the quota. And that’s, you know, sometimes enough and sometimes it’s a pain.
So, I do think it’s been very hard for collaborations that depended on people using each other’s labs, equipment in each other’s labs, shared facilities. I think MIT has done a remarkable job of containing the spread of COVID-19 whilst also, you know, trying to keep labs and activities open; it’s been a balance. But I wouldn’t say that’s been wonderful. I think it’s been hard.
And I think the people who are hardest hit in this are the graduate students and postdocs who are on their way to the next stage of their careers, and the junior faculty who have this tenure clock ticking away. And even though, you know, most universities including—many universities including MIT have extended the time to tenure and so on, no one wants to delay the rest of their life to the extent that they can avoid it. So, I think it’s been hard.
Nergis, going from being a professor where you only have your own graduate students and the undergraduate students you teach to worry about, going to dean where, depending on how expansive you think about these things, that number of people to worry about is in the thousands easily. You mentioned graduate students, postdocs, and junior faculty. What about undergraduates? What worries you about the undergraduate experience right now, and in what ways are you optimistic that this group of students is bright, they’re resilient, and they’ll come out of this stronger than they otherwise might have?
I did have a steppingstone between being dean and worrying only about my own research group, which is that I was the associate head of the physics department. And as associate head for five years, one of my main responsibilities was all things student and curriculum related. So, I have been worrying about the well-being—the education and well-being of the undergraduates and the graduate students for several years now, in the many hundreds.
We’ve learned that some things actually work quite adequately in delivering education digitally, and other things don’t. I actually think —not in everything we do, but in much of what we do—delivering content has been fine; not brilliant but fine. In some cases even brilliant, but in most cases fine, delivering content online.
I think the place I worry most is in the other part of learning, which is collaboration with other students, in hands-on learning, lab classes, research experiences in labs. I think those things have—and isolation—I think those things have really detracted from the undergraduate experience. And I have to say I’m not the only one to worry about this. I think those parts of the student population that were more vulnerable because of, you know, social economic conditions, health conditions, those are the harder hit. And so I do worry about that. Like many resourced institutions, MIT has taken many, many steps to try to address these things. But we’re not reaching everyone.
This is a conversation you’re recording for part of a historical archive, and it’ll be very interesting what people will think of this moment in time and this pandemic 20 years from now. It may be that everything we invented to deal with the pandemic is going to be the way of the future [laugh], right, and they’ll, like, scratch their heads and say, “What? They used to teach in person? People went to classrooms?”
I do think there is something lost, and I think at MIT…in the education that we deliver, and in the whole experience, you know. Students don’t just go to college to take classes. They go to college in a residential setting to really learn about the whole rest of life. Particularly when I had lectured large-enrollment physics classes, my main objective is to excite and inspire the students. And all of the detailed learning happens when they work on things with each other. I have this sort of internal motto of excite, inspire, and then get out of the way.
Right? And I think that latter part is much harder when people are not, you know, in social contact.
Well, Nergis, let’s go all the way back to the beginning. Let’s go to Pakistan, and I’d like to ask about your parents. Let’s start with them. Tell me a little bit about them and where they’re from.
I grew up in a middle-class, two working-parents family. My parents are both from a tiny minority religious community of Zoroastrians, who are ethnic Persians living in the South Asian subcontinent over generations and centuries. I grew up in this Zoroastrian family where education was highly valued, and I went to a private Catholic school. And then the greater milieu in which I lived was this—a majority Muslim country. So, I had this funny sort of pluralistic existence. Being a religious and ethnic minority was also in some ways very liberating, you know. I mean, you don’t have to conform to the mainstream, and that has been a theme through my life. I just—I really value not having to conform.
Have the Zoroastrians been a well-treated ethnic minority in Pakistan, historically?
Quite a bit. They tend to be generally very apolitical, quite affluent. They, per capita, are very affluent, with a very high sense of civic and community service. The Zoroastrians were, per capita, quite wealthy, and very committed to taking care of members of the community that weren’t. My family’s been, I would say, sort of average middle-class. We lived in a housing complex that was highly subsidized by Zoroastrian philanthropy. My parents then were able to have the money to send my sister and me to private schools, expensive private schools, expensive for there. So, it’s a very interesting community. It’s quite insular but, you know, values education and has a fair amount of economic success.
What languages were spoken in your home growing up?
I actually grew up primarily speaking English, so that’s always been my first language. My parents spoke a regional Indian language called Gujarati, but they didn’t really engage my sister or me very much in that language. I would say I can follow maybe two-thirds of what’s said. I can hardly speak a word. And I’ve also become very self-conscious about it, so I don’t speak it.
So, that was the language of the South Asian Zoroastrians, which was a regional language of India where these ethnic Persians first landed there as refugees. And then the language of Pakistan is Urdu, which I actually learned as a second language in school. So, I also never really practiced it as a first language. And then English was the language of all my schooling and at home.
Given that your family and the broader culture of the Zoroastrian community encouraged education, I’m curious if you were aware growing up that the broader Pakistani society was perhaps more conservative politically, and culturally might not have been as encouraging of women to pursue things like science?
I think those conversations were happening all the time, and they probably still are. I haven’t lived there in decades, and my family in the meantime also, for many decades, has been in Canada. So, I don’t fully know the level of discourse that happens. But, certainly, in my childhood, a few very significant events occurred that I think really changed the trajectory of my and my family’s life as well.
Two things happened roughly at the same time in the very late 1970s. The one was the Islamic revolution in Iran. The second, around the exact same time, was the Soviet invasion of Afghanistan. The third was a military coup in Pakistan that led to the empowerment of the religious rightwing. And those three things—for me as a child growing up in Pakistan—saw the rise of a very conservative militaristic religiosity. And I think that really shaped the trajectory of my family. We left, including the extended family. I wouldn’t say we left because we were particularly threatened.
The Zoroastrians—they somehow managed. I’m not quite sure. I was still very young when I left. So, I don’t fully know all the ways in which this manifests. But they sort of managed to stay above these sectarian and political turmoil that happened in the country. If I were to sort of represent them in my simple-minded way that I see it, I see them as Switzerland, you know, neutrality, neutrality, neutrality, you know.
So those three events saw this real rise in the Islamization of Pakistan. When I was a very little child, I think it was relatively—it was quite, at least culturally in the big city where I grew up is the biggest city in Karachi, it was quite—I wouldn’t call it secular, but it was at least contemporary. And then there was this very big step backwards, toward a deeply conservative Islamization. “Women can’t do this. They can’t do that. They can’t dress a certain way. They can’t speak another way.” And I think those were all the things that I think have really held back the women and the society there. But, again, I speak from a great distance. I have not kept up with it.
When did your family leave, and where did they go?
So, our trajectory was my sister, my older sister, came to the US for college. Two years later, I came to the US for college. And then once we were in college or graduate school, our parents emigrated to Canada, and not just our parents, but around that time in the early 1990s, much of the extended family. So, you know, we have much extended family in Canada, in the west coast of Canada actually, in Vancouver.
Was the pursuit of higher education for you and your sister perceived as a first wave immigration for your family? In other words, you and your sister would start in the West, and then your family would join later on?
You know, I’m not sure how planned that was. Certainly, our ability to go overseas for education, in particular why the US and not, say, England or Australia or some other English-speaking part of the world, was really to do with the American higher education system. And something that I think is incredibly valuable—it certainly changed the path of my life—and that’s the financial aid system. So, it was possible—our parents could not afford, you know, to send us to a US university by orders of magnitude.
I think that was a very big piece of it. Higher education for us was twofold. One was we as a family— I think my mother was very much the instigator of such things, but, you know, her daughters as well—we as a family just really saw that there wasn’t really a future for us not only as women but just as people interested in scholarly pursuits in Pakistan. It was swimming against the tide for us as we were the first in our generation to leave Pakistan to go to the US for university. There was a lot of worry and consternation about what would become of us, you know, going to these unknown places with mores that were not as conservative. Now, my own family, extended and nuclear, were quite liberal. So, that was the other thing that mattered.
These constraints that were coming from the Islamization of the country were really hard for all of us. And, so, yeah, so my sister came to the US. Then I came to the US two years later. And then my parents, I think, at some point, understood that we were not coming back. And that I think was the—at the time, they said, “Well, then we should get closer to our kids.” It turned out in those years, US immigration was nearly impossible, and Canadian immigration was actually quite open, so they moved.
Nergis, when did you start to get interested in science, and in Pakistan, what opportunities did you have to express that interest?
I went to this private school. It’s one of the best in the city. All around me, there was all kinds of dialogue about what girls can and can’t do. Those were not the conversations in my family, and so I didn’t have any sense that I shouldn’t do this, you know? I had natural aptitude and interest for math and science, and I went to a school where those were offered as strong subjects. So my interest came from early on, and I think the way that it was nurtured was also, I think, quite important. I had a chemistry teacher in high school who was actually very [laugh], I would say, encouraging—you know. I liked to go to the lab after hours.
The way that my school worked was after the school day was finished, there was sports in the afternoon. But if there was an hour or two to kill before your team got the play spaces for sport, you had to, you know, just sit and do your homework or whatever. I would get my homework done pretty quickly, and then I would go to the lab. And he was great. He would just let me concoct things, and I was so—I was quite mischievous, and so I liked doing things. Like, I made stink bombs.
This is before the internet, so you would have to go to the library, and look up recipes.
I was interested in Molotov cocktails, and all kinds of teenage adventures in the chemistry lab. I don’t recall if I ever actually successfully made one. I certainly didn’t try to test it. I think that was really wonderful because it kind of showed me that you can, kind of, you can do things outside of a textbook.
And then when I came to college, I think it was really sealed for me. The first time I worked in a research lab, I knew this was what I wanted to do. To answer a question that nobody knew the answer to, and that there may not even be an achievable answer, I thought that was just amazing—that plus I loved building with my hands. So, it was really important that I found myself in an experimental physics lab because—to this day, my favorite thing to do is to design and build.
Nergis, in the United States, of course, a girl who liked making stink bombs, and building with her hands would be called, in many cases, stereotypically a tomboy or something like that. Did you have that sense as a girl that larger society thought that you were doing things that were really relegated for boys to do?
I think all the time, all the time. But you can’t disentangle that with other parts of my identity. Today, I identify as a queer woman, and so there was also those elements of my identity were showing through, you know. I mean, you know, the way I dress, the way I move through the world were, I would say, certainly androgynous if not boyish or tomboyish.
So, I’ll give you [laugh] a great example. In Pakistan, I don’t know if this is still true, but when I was growing up, certainly when I was a teenager, early teens, the buses were segregated by gender. The women had the front section of the bus, and the men were in the back section of the bus. And there was an actual physical barrier between the two, and there were two different doors that you enter from.
And I remember I must’ve been like 14, 15, and I remember I was with a friend of mine, and she and I hopped onto the bus, and the bus driver started to yell at me, “What are you doing here? This is the women’s section. Go to the back.” And it was because I was, you know, dressed like a boy [laugh], and looked like a boy, to him. And, of course, the moment I said something, I was like, “It’s OK, I belong here,” and he was apologetic.
I think tomboy has many different parts that feed into that identity, you know, including gender nonconformity, scientist, athlete. All of those were things that fed into my, you know, tomboyishness.
Did you recognize your queer identity in Pakistan, or it took the education in the United States to recognize this?
No, I was actually in graduate school before I figured that out, so, yeah—
It’s not necessarily that there was a conservative society that would’ve made it difficult for you externally, it’s even within yourself you didn’t fully realize these things while you were in Pakistan?
Even whilst I was in college, I wasn’t really sure, you know. I mean, as with many young people, you know, you have to experiment with many things before you figure out, you know, the right answer. So, no, that was not at all on my radar.
What I was aware of was that it was a society that was highly constraining for women, both physically and intellectually, and with fewer opportunities. And I would say, at least at the time, to call a spade a spade, I think there was a fair amount of misogyny and sexism. And, you know, who wants to deal with that if you have the privilege of being able to do something different? And that I’m very clear on, that it’s a privilege. It wasn’t inevitable. I was among the lucky ones who could build a life elsewhere.
Nergis, what advice did you get or mentors that you may have had who made the higher educational system in the United States a bit less opaque? In other words, what kind of schools could you apply to? Where might you get in? Where might be a good place for your intellectual interests? Who helped you navigate those things?
At the time that I was growing up in Karachi, there was a handful, two or three private high schools that had a pipeline to overseas. There were not quite full-time, you know, guidance counselors, but they were faculty who knew, and you knew which other students who had gone to other places. There was a whole network of information and guidance that you got from former students, from some faculty in the school, you know. And so for me, you know, I applied probably to a list of, like, six or eight schools. I had a couple of reach schools. Harvard was one of them. They didn’t admit me. MIT was another one. Not admitted.
But, you know, so I had this list, and I had a couple of reaches. I had a couple of things that would be wonderful if I could go there. And I had a couple that I thought would be sure to happen. And that was how we did it. And this is before the common apps. You know, every app was, you know, done literally by hand. You typed each one separately. And it was also really, really expensive for a Pakistani family to come up with the amount of money it took for the application fee.
Let alone the tuition [laugh].
Yeah, I mean, tuition was completely out of reach – that was very clear. This was not going to be possible without financial aid and scholarships. I often think about this because now in my new job, I work a lot with philanthropists who give very generously to universities. I sometimes think, if and whenever I have something significant that I could contribute, it will be to provide financial aid for international students, because I think it really changes lives in unthinkable ways.
Was the intention to major in physics and astronomy from the beginning, or that developed after you arrived at Wellesley?
Physics, I came into Wellesley thinking I wanted to major in physics. Again, in high school, I loved my chemistry teacher, but I actually didn’t love chemistry as much. [laugh] I actually liked physics a lot more. I went to a high school where I was pretty early on tracked on the science and math track, so I took pretty advanced physics, chemistry, biology, mathematics. Those were sort of the tracks that I was on.
My undergraduate education was at Wellesley College. I actually chose Wellesley, in part, as a liberal arts institution because I felt like I had been narrowed too early, and I really wanted to have exposure to the arts and humanities and social sciences, and other things other than science and math, which worked out well. I really loved being able to do that. But where were we? I lost that question [laugh].
The intention just to pursue physics from the beginning.
Yeah, so, physics was right from the start. I chose Wellesley among the few wonderful choices I had because it gave me a little of everything I wanted. It gave me the liberal arts education that I wanted. But also it had cross-registration with MIT. So, I knew that when I wanted to get deeper into the technical subjects, I could just take classes at MIT. And I did, and that worked out well as well.
But once I got to Wellesley, they had this wonderful observatory with really some incredibly beautiful and very useful telescopes—useful in a sense that they’re not just your amateur backyard telescopes. Of course, they’re not top research-grade telescopes either. They’re something in between. So, I really got into astronomy; and then being a physics major, astronomy’s close enough, so I added that.
The other thing I really got into was languages, and I actually did a lot of German whilst I was at Wellesley. You’re not allowed to have three majors, so I don’t have a German major. But I actually did junior year abroad in Germany, so, you know, I did all the things I tell my undergraduates today to do. You know, don’t get too narrow too quickly. Try many things. This is the only time in your life when you can really do that.
And, so, I had this stable base of physics, and I was going to do physics, and I was going to go to graduate school. I knew that right away after I worked in the lab. I knew that to really do something meaningful in a lab, you need a graduate degree. So, that kind of got decided pretty early on. But then I did all these other things that I thought were interesting and different.
Nergis, on the cultural or sociological side, I’m sure your imagination was running wild as you were preparing to leave Pakistan to go to Wellesley. What were some of the cultural shocks that you expected, and did happen, and what were some that you didn’t see coming?
Oh, my goodness. So, you know, I spent four years at Wellesley, and then six years at MIT, so I lived in the Boston area for ten years. And then for a postdoc, I went to Caltech; so I went to Los Angeles, and I had more culture shock going from Boston—
—to Los Angeles than I had coming to Boston from Pakistan.
[laugh] That’s very funny [laugh].
You know [laugh], oh, really, you know, I could not get over the Los Angeles culture of driving everywhere. I mean, I really grew to love LA, in time. But my first year, I felt like an alien—like, really, they all drive 45 minutes to go get a meal somewhere?
You know, really, they’ll jump in their cars to do this? Really? The highways are this clogged here? All of it, you know, and, in time, I grew to love it. In time, I grew to understand that LA was really a world-class metropolis as long as you were willing to drive to everything a big city offers.
Whereas in Boston, it’s compact, you know? You can get to any place. And for most of those years of my life, until maybe a decade ago, I didn’t own a car. I was just going to take my bike—but Los Angeles put an end to that.
Nergis, as an undergraduate, to the extent that you were aware of the basic binary in physics between the world of theory and the world of experimentation, where were you on that spectrum, and how did that affect the kinds of graduate programs you were thinking about?
Yeah, that’s another good question. So, I pretty early on as an undergraduate understood that I didn’t love mathematics. In high school, I loved math. But once I started doing math in college, I realized that math was just like learning a language, and physics was the literature of that language. And so that’s how I kind of quickly understood that I had less interest and aptitude for theoretical physics because it’s much more mathematical.
And I also really love building things. So, here, I could combine my two passions. I loved physics and I loved building things, so I would be an experimental physicist. And now that’s a really important distinction, too. I was very clear that I wanted to be an experimental physicist rather than an engineer, in part, because I was still interested in sort of the fundamental building blocks of the universe. I wasn’t that interested in building to make a product. And today I would look back at my career, and say that’s almost a false dichotomy, you know. I’ve worked my entire career on building instrumentation for gravitational-wave detectors, and there’s no question about it— it is a product.
You know, it is a product with a very lofty goal, but it’s a product.
Absolutely, absolutely. Nergis, who are some of your mentors or professors as an undergraduate who exerted a formative intellectual influence on you?
The person who kind of, I think, was most influential for me developing into a researcher was a faculty member at Wellesley. His name is Robbie Berg. He was a physics professor there. And I started working in his lab pretty much within the first year after he had arrived at Wellesley as a new faculty member.
So, we had these experiences of building the lab up together. And one of the things that was also sort of remarkable was that he really had to build his lab on a shoestring. Really, there was not a lot of budget for it, which is very different than the world I experienced once I came to MIT. So, there was a lot of innovation. We built our own dye laser from scratch with parts. Today, I would never do that. My students would never do that. We would just write a check and get a commercial laser. And then what we do is we take it apart because it doesn’t work as well as the one we would design [laugh]. So, in the end, you know, I don’t know if we’re winning or not.
But when I was in Robbie’s lab, we built everything from the ground up. I had to learn to use a machine shop. I had to learn to use an electronics shop. I have this great memory of building my first power amplifier. And to build this power amplifier, I was using a particular integrated circuit chip—a power amplifier chip. And, you know, most integrated circuit parts that you would buy for op amps are, you know, really, really cheap; pennies for a part kind of thing.
But this particular device was a couple hundred dollars, and I remember, we got two because we wanted to build two power amplifiers. And I remember getting the circuit wrong, and putting in, you know, wiring it up, and blowing it up. And I, you know, I was an undergraduate, and quite naïve about these things. So, I blew it up, and then I decided, “Oh, I know what the mistake is!” and I fixed one mistake, and I put the second one in, and blew that up too.
And then so there was more than one mistake. I have this clear memory of calling the vendor—it was an Apex chip—and telling them, “I… ha…I got these two op amps, and here are the two mistakes I made, and I blew them up. And can you repair them?”
And, of course, no one can repair an integrated circuit. But the guy at the other end was just fantastic. He was like, “You know, we’ll send you a few demo pieces, and you can keep them.” And that was his way of saying, “We’re just going to replace them for you.”
That was a learning experience in terms of the mistakes made. It was also a learning experience in terms of talking to a vendor, telling them what had happened, and then seeing some of the kindness and generosity out in the world as well. So, then we got new chips.
What was Robbie’s field, and what were some of the central questions that the lab you were building were designed to answer?
Robbie’s field was, at the time, in condensed matter physics. We were looking at III-V semiconductors—so gallium arsenide—and we were looking at impurities in gallium arsenide, and how that would affect the electronic properties of the material. We were using Raman spectroscopy. So, we were specifically looking at certain transitions in the semiconductor. And by measuring the Raman spectra, we could pinpoint what kinds of defects were present in the material, and that in turn would allow the growth of a purer version.
We were sort of the characterization lab, if you will, that was using Raman spectroscopy to understand the electronic properties of gallium arsenide. So, that’s where I started. And then when I was going to graduate school, of course, you know, as most undergraduates do, that was the field I knew best. I had done some research in astrophysics as well.
On that point, Nergis, just to foreshadow, did you have any education in general relativity as an undergraduate?
No, I did not have any education in general relativity, and it’s probably safe to say I still don’t.
I regularly get emails and notices from people who want to tell me all about, you know, Einstein’s field equations, and relativity, and three manifolds and four manifolds. I tell you, that stuff, I studied it as the basis for understanding how gravitational waves and gravitational wave detectors work. My everyday work has very little to do with it. Again, it’s like learning a vocabulary, and then you just put it in the back.
That reminds me. David Shoemaker kept on emphasizing to me, he said, “Basically, I’m a car mechanic. That’s what you have to understand. I really know how to build cars”—
—“and I just do that here for LIGO.” [laugh]
Yeah, I think many of us feel that way. You know, I would say, for myself, slightly differently. Fundamentally, I’m a quantum mechanic, and I use quantum mechanics to make the LIGO detectors better. I pay attention to the relativity insofar as it informs that pursuit.
Now, you say even as an undergraduate, you had opportunity to take classes at MIT, and interact with MIT people. In what way? In what way did you know MIT even before you enrolled in graduate school?
So, I took classes here. I took some physics classes. I took some computer science classes at MIT. I had a group of friends at Wellesley who took classes with me. We took, you know, certain classes that we knew MIT was famous for, or infamous for, and we took those classes at MIT. We took the bus over. We would do classes here. We did problem sets with MIT friends. So, I had a fraction of a foot in at MIT through my undergraduate years. But then I went away for a junior year to Germany, so that, you know, took away from that time a little bit. But I did do some advanced physics classes at MIT as well.
Did you know Rai Weiss at all as an undergraduate?
No, very interestingly, I did not get to know the faculty members at MIT very well. I had this full life, you know, of knowing the faculty, and having my research lab at Wellesley, and I say my research lab because there’s a piece of me that really felt like that. It was Robbie’s lab, but I built it with him. It was mine too, you know? I think for an undergraduate, that’s really empowering to know that you kind of have, you know, keys to that kingdom, if you will, so.
Was it an easy decision to apply to MIT? Did you apply more broadly for graduate school?
I applied, you know, quite broadly to graduate school, and I had a couple of, you know, nice choices. I ended up going to MIT in part because I wanted to have the urban experience of living in Cambridge as opposed to the suburban experience of Wellesley; and I didn’t want to go to yet another suburban campus somewhere else. And I think part of it was, many of my friends from Wellesley were going to stay in the area. And so, you know, there was a whole number of things. A little bit of also just I knew MIT, I knew what I would want to do, but no—I had never heard of gravitational waves until I met Rai Weiss after I was a graduate student at MIT.
Was the original intent to continue on with experimental condensed matter?
It was, except that was only my intent, not that of the MIT faculty.
So [laugh], I had this most unusual experience, something we don’t do in graduate admissions at MIT anymore [laugh], thankfully. The way that you apply to MIT is you have to check a couple of boxes for what you’re interested in doing; and so I had checked condensed matter experiment as my first choice, and astrophysics as my second choice. And so I got this letter of rejection from MIT physics for graduate school.
And then two days later, I got a phone call from an astrophysics faculty member, Hale Bradt is his name. We still talk about that [laugh] very fondly. Hale said “Look, there’s been a mistake. You got sent this rejection letter before we had made all our decisions, so do please accept my apologies. We would love to admit you.” And so then I got this second letter saying I’m admitted to MIT. And, so, it turns out the rejection came from condensed matter, and the acceptance came from astrophysics. [laugh]
[laugh] Now we do grad admissions in a more unified way. But that was the case then. That was perhaps the happiest rejection I have ever gotten because I moved into a field that I didn’t think I would. In the meantime, I can say as an adult in the field now that I’m happy. I think condensed matter physics is interesting enough, but it’s certainly not what excites me the most about physics today. So, I feel like I landed in the right place because of someone else’s “mistake.”
[laugh] Again, just to foreshadow a little bit, I wonder if the rejection and then the acceptance, at least from the astrophysics part of it, was a recognition that you had real skills in building labs, and that these skills could be put to really positive use in astrophysical pursuits.
Yeah, I can imagine. I think, today, if these conversations were being had, that would certainly play into it because in the graduate admissions process, we value research experience greatly. I think we value it even more for students who don’t come from a large R1 university because that means they really had to work to create their research experiences.
So, I can imagine those conversations were had. I can’t say what they were exactly at the time. But it certainly was the case that I came as a graduate student to MIT, and quickly got involved in experimental work, initially on cosmic microwave background. And then a few months later, I met Rai Weiss, and then I got working on gravitational waves.
What were the circumstances of meeting Rai, and did it happen right away where you realized this was a life-changing encounter?
At the time, I certainly did not know it was a life-changing encounter. I don’t think I knew that until a decade and a half later.
But [laugh] what I did know was that this is what I wanted to do. So, the way I met Rai was, so, when I first started at MIT, I actually started working with another faculty member on cosmic microwave background, and balloon flights, which is great. You know, that’s another area—you have to build with precision. You have to get it right. Your instrument flies on a balloon.
And this is a very exciting time for CMB.
It was. Rai was very much involved in CMB as well. As you might know, he was the PI of one of the instruments on COBE. And, so, he was part of the same larger group. It was called the gravitational and cosmology group at MIT. It was Rai, and there was a couple of other people.
So, I was working with another faculty member, Stephan Meyer. And soon after I started with Steve, he was going to move to the University of Chicago and move his group there. And I didn’t want to go to Chicago, even though I loved working with Steve on CMB. And, so, Rai was part of the same larger group, and his office was just a door down from Steve, so that’s how it happened.
I just kind of wandered into Rai’s office, and I said, “I’m a student of Steve’s, and Steve is leaving, but, you know, do you have anything for me to do?” And Rai said something like “Well, you know, this COBE thing is—you know, COBE is launching and, you know, it’s kind of close to done. If you like to build things, I have this LIGO thing waiting to be built.” And so we talked about it a little bit, and, really, the interview with Rai was also quite, you know, really memorable. It’s one of the few moments in my life where I remember it almost verbatim.
So, he tells me a little bit about LIGO and building it. And then he asks me a question that went something like “What do you know?” not “What do you want to do?” He’d already asked me that, and I had replied “I like to build.” He says, “Well, what do you know?” And I was like “What do I know?”
So, I started like telling him, “Well, you know, I’m a brand-new graduate student at MIT. I’m taking graduate quantum mechanics.” And he stopped me right there. “I don’t care about that.” I think he might even have used the colorful language that Rai loves to use, like, “I don’t give a rat’s ass about that.”
“What do you know how to do?” he asked, emphasis on “do.” This bulb lit up for me. I was like, “Well, you know, I know how to use a machine shop, I know how to build electronics, and I know how to repair bicycles.” And he kind of looked at me, and he used to smoke a pipe in those days, and he would cross his legs on top of his desk. He kind of looked at me over the pipe and said something like, “Oh, I think you’ll be OK. Yeah, so if you want to work on LIGO, you know, you can join the group.”
And then I went away, and I talked to some physics friends about this LIGO thing. I’d never heard of gravitational waves. You know, this is still much before the worldwide web, and internet searches. You know, you had to go to a library and look up things. And a lot of people, including some of my graduate student friends, were, like, “This is a crazy idea, you know, don’t get involved with this. You’ll ruin your career.”
Not only that but the administration of MIT was not particularly supportive of LIGO at this point.
Exactly, exactly. And I think some of my graduate student friends got that sense from those incidences, right, you know. And, to be clear, at the time, I think LIGO was still in the process of being approved by the NSF. So, it wasn’t a done deal on that front either.
But, you know, the more I thought about this—so, there’s two things that really struck me as totally insane from Rai. The one was that we were going to build an instrument that could measure with the precision that’s a thousand times smaller than a single proton. And I couldn’t even wrap my head around how we could do that. Today, I can explain it. But, at the time, it was just like this is crazy. Even the bumps on the mirror, the surface of the mirror are more than a thousandth of a proton. How do you conceive of doing such a thing? And then the other thing that really grabbed me was that if you could detect gravitational waves, you could do astrophysics that you could do no other way.
So, those were the two things that were there. And when I put those two together, I just—I could not find a way to walk away from this. It was just too tempting to try. And I think it was a good decision because one of the things that I learned in working with Rai—and I think has been the hallmark of this whole field of gravitational wave detection— has been that when you’re pushing the envelope on a measurement by so many orders of magnitude compared to what was possible, you know, previously, you can buy nothing.
You have to build everything. Everything is custom designed and built. And, you know, for me, that was just a dream come true because that’s what I loved to do, but I loved to do it in the service of something that was fundamental to understanding the universe. So, you know, I don’t think you could’ve put me in a better place. And then there’s a third—another piece to this. Remember I told you earlier that, you know, I grew up sort of chaffing against conformity—
—and liking being at the peripheries of mainstream. And this was perfect for me because this was a completely maverick project, right? So, you know, “These are a bunch of crazies trying to waste taxpayer money doing something that will never work.”
Nergis, and as you put it, the context in terms of the nonconformity is that it was really not until graduate school where you fully came into your own identity as a queer person. I wonder if these things are sequential, if they’re tied together, or they just sort of happened in parallel in terms of you appreciating the merry band of misfits that was Rai Weiss’s lab, and the fact that your nonconformity had a sexual orientation component to it.
You know, I don’t know fully the answer to that. I was not someone, even at that time, who struggled a lot with identity. You know, there came a time when, like, “Oh, queer! OK!” you know? I didn’t have a lot of angst about it. I think it could’ve been maybe boiling in the subconscious somewhere, but it was nothing that was conscious or that I was aware of.
I think that the common thread is exactly as you put it. Here was this merry band of misfits doing something that could be world-changing, but nobody believed it would change the world because it wouldn’t work. It was the right place for me. And I have to say, you know, even though we can lovingly call it the merry band of misfits, which I love —it was a very productive, bona fide research group. It’s something that people don’t fully appreciate when they hear the story of LIGO—
—built over, you know, 25 years, 30 years. No one sustains that effort—both intellectually as the scientists who were involved, or financially as the funding agency that funds it—if you aren’t productive. We were hitting milestones year after year, and we published peer-reviewed papers. We would show how we were going to get there. It wasn’t this kind of, you know, bunch of crazies doing something that no one thought would work. People reviewed our papers—
No, Rai Weiss’s vision was singular. He might’ve been out of the mainstream but he had a vision.
He had a vision, but then he also had an execution of that vision that could realize it. We did experiments, we wrote papers; so, we were doing everything any other research group would or should do. And, so, in that sense, I think it was also perfect because I think I was doing all the kinds of science I loved to do whilst doing it with, you know, in the context of—maybe what I’m really trying to say is that my comfort with nonconformity and mavericks allowed me not to care that this may not work. I knew that even if we never saw a gravitational wave, we would invent something that hadn’t been invented before.
And, Nergis, this also speaks to—I mean, one theme that’s not developing in this conversation is careerism. You’re not terribly concerned about if these are marketable job skills on the academic search. You’re not thinking about these things?
Yeah. So, you know, that’s a really interesting and important point, David. I was an international student. I was on an F1 visa. I knew that every part of my careerism thinking had to be calculated because I was not going back to Canada—sorry, to Pakistan. My parents were in Canada. I was not. I was not a minor when they immigrated. So, I knew that I had to play that part very thoughtfully. Even though I was not a careerist in that “I’m going to do this to build a career,” I was always thinking about staying on the legal side of immigration through employment, education, etc. So, it was part of my calculations in that sense.
But what I felt very confident of was that I was learning highly useful technical skills: lasers, optics, those kinds of things. So, I felt like whether I made a career in academia or went to industry, I would get a job. Interestingly enough, when I was a postdoc at Caltech—now this, you know, in the very late 1990s, early 2000s. You know, it was the whole dotcom bubble, and everybody I knew, my graduate school friends, you know, everybody I knew was starting companies or going to work for startups.
And I would regularly get calls asking—from people I knew, sometimes people I didn’t—asking me to join their companies. By then, I had understood that I preferred being in academia. And so I was a postdoc, and then I was a research scientist at Caltech, and those companies and, you know, and sort of the financial rewards, they just didn’t tempt me. And I think, again, it was a good decision because I would say the vast majority of them folded, so [laugh].
Yeah, yeah. Nergis, back on the personal front, as you say, you didn’t suffer from much angst or identity issues with regard to your orientation. Does that mean that the process of coming out was a rather non-eventful experience for you?
Yes and no. I think for me personally, it was quite non-eventful, other than the heady rush of falling in love, and it happened to be a woman. I was like, oh, this is different. So, I would say for me, you know, my internal processes were not conflicted. They were quite, I would say, simple.
But, obviously in the greater world, you know, this is the mid-1990s, you know, family, those were not as easy to navigate. Those were harder spaces to navigate. In the worlds that I occupied at the time—so, you know, by then, I was far enough along in my PhD that—my entire world was Rai’s lab—that was a total non-issue.
You fit in because nobody fit in, kind of?
There was no issues there. I was—you know, as we started our conversation—I was a very avid and active squash player, and in that world, there was no issues either. And then in, you know, with my family, parents, it was—there was some time, I would say, timescale of months to a year of difficulty for them to wrap their heads around it. But that too passed, you know. So, I would say it wasn’t a complete non-event because there were all these things to navigate, but it wasn’t, you know, it wasn’t—on the scale of how these things go and did in fact go at the time in the 1990s, I think it was pretty smooth [laugh].
Did Rai end up being your thesis advisor?
Yeah, yeah, yeah.
And in terms of his style, was he hands-on? Was he hands-off? Did he allow you to come up with your thesis topic on your own, or was it fully integrated with what he was working on at the time?
No, I think he was actually mostly very hands-off. Early in the time that I was—you know, I joined his lab in the first few years, he also had this—you know, he was also getting COBE off the ground, you know, COBE’s launch and the data analysis. So, he was living three lives already. He had a good and well-organized group. As a new and younger graduate student, I got a lot of support from the older graduate students and the research scientists in the group, you know, including David Shoemaker, who you talked about. So, Rai was not super hands-on.
But that’s not entirely correct either. He did one of the most generous things an advisor can do for a student. At MIT, as in many places, there were doctoral candidacy exams, and the first time I took my candidacy exams, I failed. Rai went with me to look at my exam, and he looked at the things I didn’t know, and he said, “Hmm, you need to go to reform school.” And what reform school was—and he’s done this for other of his students too, I learned—what reform school was, every Saturday afternoon for two to four hours, I would go to his office, and he would teach me physics. I would stand at a blackboard, and he would say, “Alright, what if we had two spheres, and here’s a metal sphere, and remember …”—so he would make up problems, and I would have to try to solve them on the board.
And when I would stumble, he would sort of fill in the gaps of what I wasn’t thinking about, and it was like having one-on-one tutoring with the most brilliant man on the planet. It wasn’t always rosy in the sense that it exposed all the very, very many things I didn’t know. But, that was a gift because I passed my exams, and I started working in his group as a full-time researcher. And so he was very hands-off, but could be hands-on too.
I mean, three to four hours on a Saturday afternoon, for months—it was a real gift. The other thing that I really enjoyed those Saturday afternoons for was after we were done with reform school, Rai and I would go to the squash courts, which were right outside our lab, and he was also a squash player. And he took great pleasure in how good of a squash player I was. It was really amazing to me.
Rai had a friend who he used to play squash with, and this friend was not quite so tickled by how good of a squash player I was. And Rai loved to put us two together on the court, so he could stand in the back, and cackle because—well, this other faculty member that I would play with—you could just tell he just couldn’t bear that here was this, you know, small little woman who was really running circles around him. And Rai loved it. And it really egged me on because, you know, I would play him in the most cruel way, which is I would, you know, I could keep a point going forever. So, I would play him till he could not walk anymore.
[laugh] And it was one of these things; it was this thing that Rai and I had that was just ours. Rai knew what I was doing, I knew what I was doing, and we were getting some amusement out of the misplaced ambitions of this other player [laugh].
Nergis, to the extent that your thesis served as a summary of your contributions as a graduate student to LIGO, what were those contributions, and what were some of the central conclusions of your thesis?
Yeah. So, look, my thesis— it’s actually a rather straightforward problem to describe, very difficult to solve. How do you take the mirrors of LIGO—they’re four kilometers apart; they’re 25 centimeters in diameter, whatever—and how do you align them so they face each other with the precision of 10 nanoradians? Because that’s what was required for LIGO to work. And no one knew how to do that. No one knew how to solve that problem when I first started.
And there were some ideas out there of being able to use some of the geometric properties of the light inside of the LIGO resonators as a measure of the misalignment. So, my thesis really was on taking this idea that you could use the geometry of the light as a measure of alignment of a single optical resonator or cavity, and showing that you could do that for this complex multi-cavity instrument that LIGO was. I did the design, then I built a prototype in Rai’s lab, a full-fledged mini LIGO on a 10-foot by 4-foot optics table—actually, two tables by the time we finished. And I showed how you could indeed align the LIGO mirrors with that precision of 10 nanoradians. I worked with a postdoc Daniel Sigg on this, he’s a scientist at LIGO Hanford now.
Remarkably—and this I don’t say with pride, I say with some [laugh], I would say, you know, a little bit of teasing of my colleagues in the field—that technique is, to this day, used still in Advanced LIGO. And I say this, you know, with a little bit of chiding to my colleagues because it worked, but it was a terrible idea. It’s the most difficult and crazy way to do this, and, yet, we haven’t had a better idea yet. So, you know, this is one of those things where, yes, my thesis laid the groundwork for “How do you align LIGO?” The same ideas are used today, and I wish they weren’t.
[laugh] Nergis, to go back to your undergraduate experience, beyond the obvious confidence boost of building this lab and having this pride that you were able to do it, in what ways were those skills transferable to what you had done for LIGO, and to what extent were you learning new things, not just in terms of it being an entirely different science discipline but just that the instrumentation, the dealings with budget, with vendors, and things like that, was it a totally different experience?
Yeah. So, it was, actually. I think the things that I learned as an undergraduate I used all the time because they are very broad skills. I do this with even with my graduate students today where if you’re going to be an effective experimental physicist, you have to have broad training in knowing how to do mechanical design, electronic design, optical design. So, those things, I carried with me.
As an undergraduate, I learned more sophisticated versions as a graduate student. So, a machine shop is a good example. As an undergraduate, I could build, you know, some reasonably complex pieces of mechanical hardware. When I got to graduate school, I could do precision machining, so it got, you know, it got a little bit more sophisticated. But those skills, you know, translated all the time to the things that I did as a graduate student.
But I think I also did more as a graduate. One of the crazy things that happened when I was a graduate student—I was working on this alignment experiment, and this is called the auto-alignment experiment—it was going to be the prototype for what we do in LIGO. I was working with a research scientist, so a staff scientist here at MIT, who was sort of the project scientist for this. I was working on the experiment, the prototype. But he was thinking about this more broadly as an application to LIGO.
And, quite suddenly for very personal reasons, he left. He left MIT. So, I had to step in and take over the management of the project as well. So, suddenly, I was doing the Gantt charts. I was doing the budgets. As a graduate student, as a fourth-year—I think at the time, I was a fourth-year, maybe fifth-year graduate student. I was far enough along that I could do such things. This is one of those things where I would never ask any of my graduate students to do that, and no one would’ve asked me, except for this crisis that happened. It was a case of, I guess, making lemonade with lemons. And it was a very good experience because that then when I was a postdoc, I got to work with the team in LIGO that was called the commissioning and integration team.
And the commissioning and integration team is the one that takes every subsystem and puts it all together to make it work as one unified instrument. And that was really great because then I got to touch literally every part of the LIGO instrument. So, you know, I would say to answer your question, David, every skill that I’ve learned at every stage of my career has been super useful at the next stage. And you don’t always know when it’s going to be useful or how, but it just does, you know?
This is a perspective that focuses of course on the hands-on aspects of your lab work. I’m curious to what extent or not were you aware or exposed to the extraordinary complex administrative component to LIGO, the political issues with NSF, the collaboration with Caltech. What was going on with Louisiana and Washington? Were you involved in that at all? Was that above your paygrade? Did Rai shares those kinds of issues with you?
It was totally above my paygrade, and Rai liberally shared—
We talk about my graduate school years, Saturdays always will come up because—so, I told you I went to reform school with Rai Saturday afternoon, and then we played squash Saturday, you know, sort of early evening. Saturday lunch was always Rai would go to the Au Bon Pain cafe in Kendall Square, just because it was close to our lab. And anybody who wanted to go along to lunch would go along.
And, so, you know, a handful of us, three or four of the graduate students would always go, and Rai’s good friend Ziggy, who was a professor also at MIT, but also what happened to be Rai’s first graduate student. So, Ziggy and Rai are not that far apart. Ziggy is since deceased.
And they would talk, and the rest of us would listen, and Rai would just describe the events of the week. “Oh, I went to Washington, and this senator did this, and this congressperson, and this staff person”—and he would describe in great detail all the machinations that were going on in getting LIGO off the ground politically. And, so, we could—you know, we followed it.
I certainly—and a few of my fellow graduate students found it interesting. We would ask questions and Rai is also—I’m sure you’ve talked to him. You know, he’s a fantastic storyteller, and he was even then. So, even these mundane, battles in Washington would sort of come to life at lunch, and Ziggy was a great instigator. Ziggy would always ask Rai questions that would provoke Rai into colorful language [laugh], and so it was really great fun. So, yeah, we did—if you wanted to. Not everybody in the lab came to the Saturday lunches or wanted to. But those who came, we always got regaled with sort of the stories of the week, including science. Some of it was science, you know. “Did you see this paper that came out? It’s all rubbish,” or, “Oh, did you see this brilliant thing that someone did?” So, we got Rai in those kinds of vignettes.
Nergis, to outsiders, of course, one of the false assumptions with LIGO is that it’s worth was only really proven with the actual detection of a gravitational wave, which, of course, for your tenure as a graduate student, is a long way off, right? To what extent when you had finished up your graduate experience at MIT was there optimism that the gravitational wave would be detected, and did you see it in those terms, binary terms, where LIGO was successful with the detection, and it was unsuccessful without?
I did not see it in such a binary way. I think of LIGO as having two or three purposes. Certainly, the biggest and greatest purpose was to detect gravitational waves, and I had, most of the time, great optimism that we would. Occasionally, I would be like, “Oh, my goodness!” you know? My uncertainty never came from worrying would we build a good enough instrument. I was sure we would eventually.
My uncertainty came from “What does nature do? Does nature really make these waves the way we think they should be? Are they as powerful as we think they should be, or as faint as they think”—so, that’s where my uncertainty came from. I would say, certainly, I had moments of doubt whether we would ever detect gravitational waves. It usually came from “What’s the astrophysics of the sources?” But there’s the other purpose of LIGO, which was that it was pushing the state-of-the-art in precision optical measurement that was having all kinds of repercussions in other fields and areas, in particular in atomic and optical physics.
The technologies we used to stabilize the laser are absolutely workhorse in every lab and, you know, those kinds of things. So, I did not feel that was an all or nothing there. And it comes back to the thing I said earlier. It wasn’t all or nothing. We were publishing in peer-reviewed journals, and so we were doing things that other people were interested in, you know.
When you were considering postdocs, going to Caltech, was the specific intention to continue on with LIGO there?
Yeah, very much so. I joined the LIGO group at Caltech. What I had done for my doctorate, my PhD thesis, was a prototype of LIGO that was mirrors fixed to optical tables, but it had the geometry of LIGO, and we showed that we could align the instrument. What I wanted to do next was to get some experience with actually working with mirrors that aren’t fixed to tables, because LIGO’s mirrors hang like pendulums. And it turns out when you add the dynamics of those mirrors to an experiment, it’s a completely different experiment. It’s like looking for Higgs bosons, and then looking for neutrinos. That’s how different the instrumentation and the other parts of the experiment get to be.
I wanted to branch out, and do suspended mirror interferometry, which was happening at Caltech at the time. And quite soon after that, about a year after I arrived as a postdoc at Caltech, the buildings of the LIGO observatories were ready for installation of the scientific apparatus – the first detectors. That’s when I kind of got involved in the commissioning and integration. And I have to say when I sort of look back at my scientific career, I have many, many chapters that I’ve really enjoyed. But that one really stands out. We were at the frontier, you know.
We built the first ever 15-meter long optical cavity. And then as soon as that was working, we had to build a two-kilometer long optical cavity. And they’re completely different beasts. Then there was another thing that I would say is kind of different about working on the main, big LIGO instruments compared to your sort of lab prototypes, which is that at some point, it becomes too big to fail, which means that, you know, in your own lab, you get stuck, you know, you have to fumble, and you make it through. And if it doesn’t get solved, you find a workaround.
With the big instruments, you had to make it work. So, it was really all hands on deck. I worked with some really brilliant people, and that was fantastic too. Brilliant people who all had one singular goal, and that was to make the damn instrument work, and work as well as we needed it to, and said it would.
Did you have opportunity to interact with Barry Barish and Kip Thorne when you got to Caltech?
I did very much. Barry was officially my postdoc advisor, although I worked much more closely with Stan Whitcomb, who was the director of the science—LIGO scientific director, I think he was. But, yeah, Barry was officially my postdoc advisor. I’m not sure I ever really worked with Barry in a technical capacity. But, you know, he was the person I went to for things like career advice and things like that.
And Kip, I’d never worked with also directly. But I actually collaborated with Kip’s graduate students and postdocs, and we wrote a couple of theory papers together. So, I have intersected with them all in close ways.
Nergis, you emphasize the culture shock of going from Boston to LA, but you did that more on a societal or a cultural level with regard to cars and things like that. What about the culture of the department at Caltech? In what ways was the different from MIT?
That’s a nuanced answer because when you’re a postdoc, you really are going to your research group. You don’t have a lot of need to have contact with the larger department. You know, the LIGO group at Caltech was quite big at the time. It was 30 or 40 people big, maybe more, maybe more like 60 or 70. So, I could never leave LIGO land and wouldn’t notice it.
Now, that wasn’t quite true for me because I had this other life of playing squash. So, I knew a lot of people within the Caltech community that way. But the differences between the institutions of Caltech and MIT, the most obvious one to me was Caltech was tiny compared to MIT. And MIT’s not the biggest place either, but Caltech was really, really small. So, it was possible to get to know many, many people.
The weather is almost always really nice, so I was always amazed by how many people weren’t in their offices after 5pm. I didn’t know quite what to make of that, I was coming from this crazy northeastern work ethic, and I don’t even think it’s such a good work ethic. We think because we work a lot, we work better, and it’s simply not true. But, so, that really puzzled me.
And then I understood that people go out, but then they come back around 8 or 9pm, and work into the night. So, it wasn’t all that different after all. I would say there were not huge cultural differences between Caltech and MIT, other than Caltech was much smaller. There were notably many fewer women. But that was, I think, maybe the main things that I noticed.
Nergis, to go back to the question about careerism and employability and being able to stay in the United States, when did you start thinking about citizenship or a more permanent status so that you wouldn’t have to worry about these things long-term?
I would say at every stage of my career, almost every decision I made for career was informed – or certainly strongly influenced by – that question of how to remain legally in the United States. The way that happened for me eventually was I was a postdoc at Caltech, and when I finished two years of postdoc, I told Barry and Stan that I really, really needed a green card, and asked if Caltech could work on that for me? I was actually converted from being a postdoc to being a staff research scientist so that Caltech could do the paperwork for that. And soon after that, I got a green card, so it was, you know, through that process. I think that was shortly after I was a postdoc, whilst I was still at Caltech—my green card was done. And that sort of made a big difference, and I think I became a citizen like the day after my probation period was over [laugh].
Nergis, there’s so many people who have made a career within LIGO on the non-academic faculty track. Did you ever consider that, or were you always focused on having teaching and mentoring students being a part of your research agenda?
No, I was completely not focused on that. The way that I ended up joining the faculty at MIT is that I actually got a call from the chair of a faculty search committee at MIT saying, “We have this search open, and won’t you apply?” My very first reaction was, “No, I won’t apply. I have friends who are applying, and they’re much better than I am. So please talk to them.” But then the search chair sort of said, “Look, you know, we just want to look at all applications. Won’t you apply?” So, I stuck together an application. I put in my research statement some rather futuristic— at the time—ideas about what I could work on, but I wasn’t really thinking about it seriously, not because I wasn’t serious about the job, but I didn’t have any inkling that it was remotely possible I would get offered the job. And even if I did, did I even want to do it?
So one thing led to another. I interviewed at MIT, and I got offered the job, and then I actually wasn’t sure I was going to do it, because I was having such a blast. I was working—I don’t know—25 days a month at the LIGO observatories. I’d go back home to either Caltech or New York, where my then partner lived, for a few days a month. It was the perfect unfettered life of doing exactly what you love to do without having to do the parts you didn’t love to do. I could spend LIGO money without ever having to think about where it came from because that’s what the higher-ups were responsible for. And I could influence the science because my work and ideas were taken seriously by said higher-ups.
But then I talked to Barry, and that was a very pivotal conversation because what he laid out was something that I hadn’t fully appreciated at the time. He kind of talked a little bit about “What if you have ideas that you want to execute that you can’t do in the context of a project like LIGO?” Because as a research scientist, you’re beholden to—most of your time is committed to the project’s needs. And faculty life gives you freedom to do that. It gives you freedom to supervise students. I was like, “I don’t need that freedom. I already do supervise students, you know.” But, as we talked about that, I kind of understood that the trajectory for a research scientist was more limited, and that maybe eventually I would outgrow it. And that was sort of the turning point for me.
I was not thinking about an academic career at all. I loved what I was doing as a research scientist at LIGO. And now, in retrospect, when I look back, of course, that was naïve because even research scientists have to grow up eventually, and start acting like responsible adults, and that would have happened for me as well, but, in the meantime—so, no, I was not planning an academic career. It somehow landed—you know, I landed the job, and then I had to decide whether to do it or not. And I was somewhat reluctant about it, but then—as soon as I started as a faculty member, I really started enjoying it, teaching, building my own group, new ideas, new science, all of that. So, you know, it was really totally worth doing, but it wasn’t what I planned.
What came next for you? What was the next big decision?
So, I think the next turning point for me—so, I had been working specifically on the LIGO instruments. My PhD was “How do you align it?” And then I—my whole postdoc and research scientist time, those five years at Caltech was building the first LIGO instruments, you know, both at Washington, at Louisiana, you know, really solving problems in the field. But then I came to MIT as a faculty member, and two things happened. My ability to spend 25 days a month at the observatory suddenly eroded.
And then there was this other, you know, sort of annoying naggy thing that was that, you know, tenure had to be made. And part of the advice I got from senior faculty at MIT was that, you know, “LIGO is unlikely to have results in the time to tenure, so you better do something useful in addition.”
And at the time—so, this is this perfect confluence of being at the right place at the right time—I had just come off of this postdoc scientist period at Caltech where I’d been collaborating with Kip Thorne’s group on Advanced LIGO. So, we were building LIGO, but we were already thinking about the technologies for Advanced LIGO. One of the early things we recognized was Advanced LIGO was going to be completely limited by the quantum noise. And, you know, what could we do about that? And so—
And this is just very—just to interject there—this is a new question for Advanced LIGO? This is not necessarily relevant for LIGO?
Yes and no. One part of quantum noise – the shot noise – was also a problem for Initial LIGO. But the other part – radiation pressure noise – is only a problem once the laser power is high enough, and it wasn’t until Advanced LIGO. The whole concept of quantum noise was around in the ’70s and early 1980s in its full form, which is that it limits our ability to measure the phase of the light —known as shot noise, but it also disturbs the mirror position due to light momentum kicking the mirror and causes a displacement—known as quantum radiation pressure noise. That’s the full version of the quantum noise.
Further thinking about quantum radiation pressure noise was sort of shelved after the early 1980s because in the first incarnations of LIGO, there just wasn’t enough laser power for the quantum fluctuations to matter in terms of kicking the mirror. So, the shot noise limit we knew. It was well studied.
But now, in the early 2000s, came this problem that we’re going to build this new instrument. We’re going to put a lot more laser power in there to make it more sensitive. But because you have more photons, you have a larger number of photons kicking the mirrors, and so those kicks are going to now start getting in the way. So, you bring your other displacement noises down, you increase these mirror kicks, and suddenly you have an instrument that’s completely limited by the quantum fluctuations of the light, and what do you do?
And that was really a big crossroads for me. As a new faculty member at MIT, I said, “Well, we have these theoretical ideas out there that have been out since the 1980s on what to do on things like squeezed light and quantum nondemolition measurements. But I’m an experimentalist, and so none of this theory is worth much unless we can show that it works, and we develop the technologies for it.”
So, that was the path I went on in 2002 when I started as a faculty member. And I’ve been on that path ever since because as Advanced LIGO got designed and built, we knew that we needed all kinds of quantum sensing and quantum enhancements, and that’s what my group has done ever since. I think it was also again a good decision to do that. I tell my students this as well—and maybe I didn’t know it at the time—or maybe I only knew it subconsciously: One of the most important skills you have to develop as a scientist is a good nose for where the most interesting problems are. You can have all the technical skills you want, but if you don’t apply them to important, relevant problems, you’re underutilizing those skills. And I think that’s what happened there -- I stumbled upon an important question to answer.
And, Nergis, on that point, the question of getting advice from more senior faculty that during the tenure clock, the gravitational waves likely won’t be detected, so you need to branch out a little, is the development of your interest in skills in quantum measurement, is there a duality there where it’s both responsive specifically to Advanced LIGO, but it’s valuable for the field generally, and it will enhance your tenure prospects irrespective of Advanced LIGO?
You know, the way it started was very much focused on Advanced LIGO. So, what do we need to do to make Advanced LIGO better? Well, we need quantum sensing. So, I started to study what’s been done in quantum sensing before, and sort of married Advanced LIGO’s needs to the field of quantum optics, if you will. But then—and some of this again quite fortuitously—it kind of took on a life of its own. Initially this line of research was entirely geared towards Advanced LIGO, but before long I understood something really important. The technologies that were developing for Advanced LIGO have much broader applicability to precision optical measurement, and that’s how that went.
So, I’ll give you a remarkable example. My students and I were building an experiment in our labs at MIT, yet again another prototype version of LIGO or Advanced LIGO, where we were trying to experimentally observe the effects of radiation pressure that were expected to show up in Advanced LIGO. In Advanced LIGO, why do you have radiation pressure? You have a honking large amount of laser power—you have so much laser power that even this 40-kilogram mirror of Advanced LIGO is kicked around by the radiation pressure. So, we were trying to reproduce that in our lab. But instead of using a 40-kilogram mirror and a megawatt of laser power, we’re using a 1-gram mirror, and kilowatts of laser power to reproduce the same light-mirror interaction.
And when we do this, we make a very strong coupling between the mechanical motion of the mirror and the light. And it turns out right around that time, sort of mid-2000s, there was a really brand new field taking off that had sort of started more in condensed matter and mesoscopic physics with nanoscale mechanical objects. It’s called quantum opto-mechanics. So, it’s taking—literally taking an optical mechanical coupling, using the radiation pressure of laser light to push around a mechanically movable object—usually a micro- or nano-scale mirror.
And, so, we had inadvertently with LIGO built an incredibly precise opto-mechanical system. It appears that I was not up on the opto-mechanics literature. I went to Yale to give a colloquium. And my dear colleague and friend, Steve Girvin, who’s a wonderful person [laugh], and someone from whom you will get a rich history of things to talk about.
My talk at Yale was along the lines of “Here is the radiation pressure problem in LIGO, and here is an experiment we’re building to try to see what it would look like in this.” Afterwards, Steve asked me, “Have you measured the temperature of your mirror?” And I said, “That’s a crazy question. It’s a room temperature system. We don’t do anything to it. It’s not cryogenic.” He kindly explained “No, but it must have some effective temperature because you’re coupling this hot mirror to this cold optical field.” I said, “I never thought about that.”
And, literally, as I was taking the train back to Cambridge from Yale, Steve gave me a paper, and said, “This is a paper that came out a few months ago. You should look at it.” And I looked at it whilst I was on the train coming back, and from the train, I called my graduate student, and said, “We have an interesting measurement to do.” And within two weeks, we had made a measurement on our system that was instigated by this paper, but it was on a system that nobody had access to because nanomechanics is really different than this macroscopic gram-scale object. And that started off a whole new area of research for me, and that’s been very productive as well. One moral of the story is that when Steve Girvin tells you something, listen.
[laugh] Nergis, to go back to the tenure question, what was the culture of promoting from within at MIT at that point? You hear about like at Harvard or Stanford, places like that, junior faculty are essentially glorified postdocs, and the trajectory is you should not expect to get tenure. Was that you sense of how things worked at MIT, or that was not the case?
No, it was not the case. Look, it was very much—what was communicated was we select very carefully, we bring you here, we resource you, we very much wish for and expect you to succeed at the time of tenure. That was the message that came across, and I believe that was always what was enacted. What was slightly dissonant with that was that the tenure rate was not high. Of all the junior faculty that began, at least at the time when I was coming through the system, only one-third got tenure. So, there was the numbers, and then there was what was said.
I didn’t for a moment think I was, oh, so special myself, that I was going to be in that one-third that gets tenure. What I did know was that I wasn’t worried that I wouldn’t get another good job. Really, that was what it was about. And that gave me a lot of freedom to not fret about the tenure thing, and I didn’t. I actually did mostly did exactly what I loved doing. I can’t think of a single time when I had a calculation that if “I do ‘X,’ that’s good for tenure.” My calculations were always “I’m an academic; my productivity is the students I educate, the papers that I write, and the interest that those papers generate.” So, that was what motivated me. And that’s, of course, related to tenure. It’s not independent of it. But it wasn’t calculated in that way.
Nergis, to what thought—what thought did you give in terms of how closely you wanted to rekindle your relationship with Rai as a graduate student because now you’re part of the faculty? Did you have any inkling that it would be better to establish some buffer because you’re no longer a graduate student, you’re at a different place in your life, in your career trajectory? How did you think about those things, if at all?
You know, I did think about it a little bit. Rai and I have always had—we’ve had a somewhat independent relationship as well, you know. I was not the kind of graduate student who depended on him for my every move. Neither he nor I would’ve liked that. As a graduate student, I had other day-to-day supervisors, and I was also quite, you know, free-spirited myself. So, I wasn’t so worried about creating a buffer. I would say certainly by the time I was a postdoc, and working at the observatories a lot, and Rai would come and go, we had much more of a peer relationship.
There were many things that I knew better than him, even though I would say in the grand body of knowledge, even to this day, he knows infinitely more than I do. So, I wasn’t worried about that. And then the other part—the thing I wasn’t worried about was I knew that he was very good at creating space for me.
I think that’s really important, and something that’s not very well understood is that when you have a new faculty member coming into a field where there is a much more senior and established faculty member, the new faculty member is not going to succeed unless the established faculty member makes room for them. And Rai was very good at that. Never spoken, nothing was said, but I could just tell.
So, this quantum work went in a direction that was really mine. I never had any thought that, you know, I have to distinguish myself or make myself independent of Rai.
As you were developing the expertise and the interest in quantum measurement, in what ways did you see that it was really applicable to Advanced LIGO in ways that you might not have anticipated, and in what ways did it confer benefits and new research opportunities beyond LIGO?
Yeah, so, I think a few things. When I was getting started in the quantum measurement work, there were three research groups worldwide that were involved in this quantum noise for gravitational wave detectors. Certainly my group at MIT. But also David McClelland and Ping Koy Lam’s group at Australia National University were big players in this because they already begun thinking about squeezed states of light.
Ping Koy was doing it more from the point of view of quantum teleportation experiments. But David McClelland, who was part of the same group, was thinking about it for gravitational wave detectors. And then they had a postdoc, Roman Schnabel, who became a faculty member in Germany about the same time that I started my faculty position at MIT. So, we three got together, Roman’s group, David’s group, and my group, and we formed a loose sort of consortium or collaboration.
We laid out what were the problems, and each of these labs was pushing on different aspects of particularly squeezed light. So, for squeezing, these were the three groups that came at it together. Now, the place where I think I had the greatest advantage compared to David and Ping Koy’s or Roman’s groups, is that I was part of LIGO Lab, and so the technologies that got developed as part of this consortium, my group was in the best position to quickly import them to LIGO. And that’s something that many physicists don’t appreciate unless you work on large experiments. The process by which a tabletop laboratory demonstration gets ported onto a large scientific instrument, there’s many, many layers and steps to it—everything from this design and engineering to actually commissioning. So, I had some advantages on that. They were processes I had done before for many subsystems.
So, we would make discoveries in our labs, and I could quickly port them to prototypes and then to LIGO itself. You asked the question—What was relevant to LIGO? I would say I think the main driver was always “How is this good for LIGO?” And then all these other offshoots came from that, including the opto-mechanics, the quantum opto-mechanics I talked about, which has grown into a vibrant field of its own. The mechanics we use are huge, right? LIGO has big mirrors, and everybody else uses, like I said, nanoscale, microscale things. And we have some nano-micro experiments as well as proofs of concept. But that would be the divide.
I have at times had students who—we start to think about some applications of some of our technological developments to, say, quantum information, so quantum computing. I often let myself get pulled by what students’ interests are because they’re the next generation in defining, sort of the pioneering the field, if you will. But somehow when I see it’s too far from what we need for LIGO, I haven’t gone there.
[laugh] That’s a great point.
[End of Session 1]
[Start of Session 2]
OK, this is David Zierler, oral historian for the American Institute of Physics. It is April 26, 2021. I’m delighted to be back with Dean Nergis Mavalvala. Nergis, it’s great to see you again. Thank you for joining me.
Thank you, David. It’s good to be here.
Alright, so, our first talk was on February 18th, and, in a COVID timescale, that was a very long time ago. We weren’t talking about vaccines in mid-February. And, here we are in late April, where we can start to have maybe very preliminary conversations in higher education about life getting back to normal. So, I’m curious, in the interim, what is the latest thinking at MIT? What might a fall semester look like?
I think it’s still very much under discussion, you know. There are internal principles and guidelines. There’s guidelines from the state and the city, so you have to balance them all. But I think there is some guarded optimism that, you know, we will be fully residential again, and that some good fraction of the instruction if not most of it will be in person. But, at the moment, this is all still being discussed—
And given how important—
—and there’s no commitments yet.
Given how important international students are to MIT’s identity, to its mission, what are some of the challenges there in terms of people coming in from all over the world?
Yes, I think that’s another thing that has—is being given a lot of thought and care. I think there’s more uncertainty there. There’s two kinds of uncertainty there. The one of course is pandemic-related, and the other is visa processing times related which was quite decimated over the past few years and, you know, there’s a recovery time to the State Department [laugh] getting operations back. So, no, I don’t really have a quick answer on that, other than that it’s very much part of the planning conversations that are going on.
OK. Well, let’s pick up our narrative in the 2014/2015 area, and let’s start first with LIGO. It’s so fun to hear everyone’s individual perspective on when things started to get exciting, and what feedback in terms of the data, in terms of just the buzz among your colleagues—for you, building up to the actual detection itself, was this a gradual process? Was this a Eureka moment? How did this play out in real time for you, and when exactly did it start?
We could look at the beginning of 2015 and the move along from there. LIGO had been down as an instrument for almost five years. This was a big upgrade from initial LIGO to Advanced LIGO. And, for me personally, my group was working on quantum technologies that were going to be deployed in the next phase of Advanced LIGO. So, the very first phase was not going to have squeezed light sources, for example.
I had been looking at the detector coming online, slightly from a distance. I was looking at the detector coming back online with an eye towards the quantum technologies we were going to deploy. And, of course, I had students working on it at the time. And, so, when we knew that the first observing one was going to start, and we knew that we had a sensitivity that was notably improved compared to initial LIGO, and that was very exciting.
I had no real inkling that it would be good enough to see something right away. And, to be honest, anybody who thought that was even more optimistic than I was, and I’m an optimistic person. [laugh] So come September 2014, and we record a signal that’s enormous, the very first—my very first thought was, oh, it’s a blind injection. This is the process by which we validate our data analysis techniques by putting fake signals secretly into the data stream, and then seeing if the analysis pipelines will pick up those fake signals that we injected. And, so, I thought that this is a blind injection.
It turns out pretty quickly, being in the instrument science team, we know which channels can be used for injections. And you can see from the logs whether those channels were engaged or not, and they were not. So, then you can imagine that the other thing, of course, which was if it’s not a blind injection, was it a spurious, you know, instrument glitch? And the third of course was, was it a malignant sort of incursion into the instrument?
What would that mean, a “malignant incursion”?
Oh, so, someone, a hacker, whether from inside the collaboration or outside, had somehow managed to inject something into the data stream. And, again, because we know all the entry points into the data stream, you can check whether something like that happened. But that process took a few days to be sure, and so this is all a long-winded way of saying the very first time I saw the signal, I didn’t have some, “Oh, my goodness, could this be the one?” I had more of a, “Well, where are all the different ways in which this could not be the one?”
Right? So, there was a real skepticism about it. And, you know, I have to say, in hindsight, that is exactly the right reaction that scientists should have, you know. Of course, the storybook version is that you had this moment of, you know, “Oh, my goodness, we’ve seen it!” But the real scientific response should be one of skepticism and suspicion, and that’s what it was. It took a few days to determine that it wasn’t a blind injection, a malignant injection, or any kind of known or knowable instrument glitch. But then it took about two more weeks till we had collected enough data that you could make a true statistical estimate of the background noise in the instrument, and then make a true signal-to-noise ratio for this event—to give some quantitative estimate of how likely is it that the instrument’s own glitchiness would generate a signal like this.
Now, Nergis, in this scoring system, is it similar to all of the excitement at Fermilab right now with the muon anomaly where they’re talking about a 4.2, and everybody will get really excited if it gets to a 5? Is this the same system?
You know, it’s pretty—it’s very similar. But what does the 4.2 or the 5 really refer to, right? It refers to how strong is your signal above the background of noise? And the signal, at least in LIGO, lasts just a few hundred milliseconds, so a fraction of a second, and the background of noise is something that you estimate over time. Because you’re looking at how often does a rare event happen, you have to look at enough time to make a catalog of all rare events, including rare glitches of the instrument itself. And that takes time.
So, you can have a sort of a quick look signal-to-noise ratio that says, here’s the signal. Here is the noise in this small little stretch of time around the time of the signal. But, really, to do good statistics, you have to look at the noise background, the statistics-to-noise background over a long period of time, and for us, that was about two weeks. So, we collected more data in LIGO for roughly two weeks, and then we did that analysis again, and there was this moment, and I think that was the moment for many people.
Although, I have to say, after the first three or four days, we had sort of negated the possibility that it was these really, you know, outrageous things. People—and including me—we were starting to get excited. This could be real. The most obvious ways in which it would not be an astrophysical signal, we had eliminated. And there came this moment, I think it was October 3rd of 2015, that there was a collaboration-wide conference call in which the data analysis pipelines, two different analysis methods, were going to unveil the results of these analyses. And that, I think, was the moment. If there was a moment where sort of the goosebumps spread, I would say that was the moment when those analyses were unblinded, and you could see with very high confidence that the signal-to-noise ratios of these—this event was huge.
The probability of the observed signal being an instrumental glitch was like one in 200,000 years. So, you would have to take 200,000 years of data to create this event as a pure accident in your instrument. And once you have a number like that, you can say, OK, you know, nature has spoken to the instrument, and the instrument has recorded her message. And then came another whole few months of really checking every other possibility, different kinds of analyses, and another really fun thing which is the more—the better the signal-to-noise ratio, the more accurately you can estimate the parameters of the system. So, you know, “What were the masses of these black holes? Were they spinning? How far away were they?” And all of those numbers, we had answers to pretty early, but the error bars got smaller and smaller as the analyses got more sophisticated.
Maybe this is a naïve question, Nergis, but what you’re saying is, quote, unquote, seeing or detecting the gravitational wave is really a matter of analyzing the data? There isn’t some independent way to interact with this gravitational wave? It’s simply what the data is telling you?
It’s kind of true for most ways that we do measurements, and most of the ways in which we characterize nature. If you look at data from a telescope, you know, yes, you know, it can feel more visceral because it has a visual image. But, in the end, the science that you extract is not from the visual image as seen by our eyes, it’s actually from looking all the different physical parameters that are encoded in that image. So, for LIGO too, you know, actually just by chance, this was the—
There you go.
Let the record state that Nergis is wearing a T-shirt that has the waveform of LIGO’s first detection on it right now. That’s fantastic.
All those bumps and wiggles of the wave, their spacing, their height, their relative offset from each other in the two instruments, those are all the things that give us information about the source.
So, when Steven Spielberg does LIGO the movie, and he films this wave coming from the primordial universe to planet Earth, that would be a fictionalization of what can be seen?
No, it’s real. Our eyes don’t see it, but it’s real. It’s really a wave of the spacetime itself. It’s propagating like a wave. It comes through the Earth, and ever so slightly jitters everything as it goes by. All of that is correct. It’s just that the way that we visualize it is different, right. It’s very much like if you were trying to recreate an image of something really small using an atomic-force microscope. You know, you’re recreating the image of something your eyes actually can’t see, and you use instrumentation to create that image. And this is very much the same, you know. So, yeah, so that’s where we were.
Back to 2015, two other things happened that I think were very significant, even though the world didn’t or couldn’t see them at the time. First, why was it that within literally hours of turning on the instrument, we saw that first event, GW150914. And then, second, why didn’t we see anything else? Was this the only pair of black holes in the universe that were colliding?
Then came two other observations. One was a pretty weak one. It was well below the five-sigma certainty that we like to quote, at least in those early analyses, in October. And then in December, there was a stronger one that met, again, the five-sigma requirement. And even though we weren’t ready to announce those to the world because analyses were still going on, etc., when we announced the first one in February 2016, we already knew about these other two.
And I think that’s really important, again, for the way science is done, which is, you know, a one-off is something to be suspicious of. Those were kind of the—in that first observing run, which ended at the end of 2015, and then we put out the result, the first results in February 2016, I think that was the build-up. The number of checks and balances that were done on the events, and that we had at least one confirmed and one likely other observation, were all really important in building our confidence that this was astrophysically real and significant.
Plus, you have the redundancy from Washington and Louisiana.
Right, exactly. And, in fact, the time delay between the observations in the two detectors—it was an important way of knowing the patch in the sky where the source was located. So, that’s also used for localizing the signals. Some of these possible ways in which this could go wrong, like an injection into the data stream, whether malignant or intentional or blinded, those would affect both data streams, you know. So, you had to be careful about checking those things in a sort of a cross-referenced way.
How important was the collaboration in the early period of data analysis to be leakproof, that word could not get out about this data, and who set that tone for the importance of keeping this in the LIGO family, so to speak?
That’s a really good question, and one that I would not have predicted would have gone so well. And—
Just because scientists are gossipy, you mean?
It’s not even gossipy. I think that there’s also so much excitement and, you know, and so I think there were a few things that I can say about that, and these are my own personal observations, you know. Part of—you know, the collaboration on the whole worked really, really well together. And I think it’s in part because everybody had an important role to play.
For me, as someone who works on the instrument, I can build the most fantastic instrument in the world, but without good analyses tools, we’re never going to be able to take full advantage of the data. People who work primarily on the data will have no data if people [laugh] like me aren’t building the instrument and getting the data. And I think we understood that symbiotic relationship very well.
And there is a third piece to this that doesn’t get as much coverage as it should, which is that the data analysis was supported by a very big theory effort as well. You know, “What do the waveforms look like? What will the gravitational waves look like from different objects and under different physical conditions?” And, so, I think those three things had to come together over decades of work.
One was building an instrument that was sensitive enough, sort of refining the theory so that you actually could make some predictions for what the waveforms would look like, and then encoding those waveforms into analysis tools to actually extract meaningful results from the noisy data. And those three things had to come together in a very symbiotic way. So, I think in part, the collaboration worked well because everybody was in it in a way that everybody had to do their share to make it work.
And then I think the other piece was that I think the collaboration was also very, I would say—I would say there was a certain amount of democracy and transparency in it. And, you know, maybe the younger people, like students [laugh] and postdocs, wouldn’t agree with that. But, so, you know, I think the leadership really tried to make things very open in terms of anyone in the collaboration could come to the meetings, could weigh in. I know the paper that we wrote was an amazing feat. There was a paper-writing team that really pulled together ideas from all parts of the collaboration. I think that by the time the paper that was put out to the world, it was probably like version 30.
You know, and I would say every word was considered by as many people as wanted to engage. And so I think between sort of the democratic approach and the transparency and this idea that everybody had a role to play, an important role to play, was all the things that kept the collaboration aligned and relatively leakproof.
Now, was the NSF on the inside for this? Were there people who knew everything that was going on?
Sure, very much from the start, you know. I mean, NSF has been an incredible and singular partner for decades on this. And, you know, I think, for my own self, when I finally understood that we had seen something and, you know, appreciated it, one of—among the many emotions that I felt, I kind of felt—I remember at some point thinking about it, and, you know, I was Rai Weiss’s student. I’ve known him for decades. I’ve known the important role he’s played in—the incredibly important and crucial role he’s played in launching this field, and I just kind of—I had this thought about, you know, “This one’s for you, Rai.”
And then the next thought I had was, you know, all the people at the NSF who kind of stuck with this—and, you know, we can think of NSF as an organization. But, in the end, it was the scientists and the leadership there who over decades supported this, and I kind of felt like this one was for them as well. They took a risk, and no one knew if it would pan out. And scientists like me were going to have a ball regardless.
You know, we love building instruments. We love the science. We love the challenge. We love the precision measurement of it. But, you know, they had some real answering to do, you know, [laugh] to Congress and others. So, I kind of felt like, you know, yes, they were part of it, and they really absolutely should have been, and were.
On the question of emotional responses, did you ever reflect on the poetry of contributing to verifying Einstein’s prediction from a century earlier?
Yeah, you know, a lot. At that time, and in the years since, I’ve also studied a bit more, Einstein, history, the history of the field, Einstein’s own role in it, and I think I’ve really come to understand—I mean, everybody thinks of Einstein as brilliant, and he was. But I think he also really thought outside the box. He was happy to go against the conventional wisdom of the time, and through his field equations, which encode the gravitational waves in them, he really gave us sort of the recipe for how the gravitational universe is put together [laugh].
I’d like to hear your perspective—
Now, is it the—
Yeah, please, please.
Yeah, I was going to just say is it the last word on gravity? I don’t believe so.
Sure, it can’t be. We’re not there yet.
But it is certainly the best description of gravity we have at this moment in time, and for the precision of observations we can do.
Within those limitations, do you see LIGO specifically contributing to a more existential goal in physics of unifying all of the forces?
Hard to say. I think gravitational wave detectors of the future, as we get to greater sensitivities, will certainly be able to weigh in on this. In particular, if we ever get to the sensitivities of being able to observe quantum phenomena around black holes, for example, the kinds of things that are, again, encoded in some of the theory, but we have not had any way of observing. So, I’m not so sure.
I do believe in the future, they will play a role. I don’t think in the current levels of sensitivity, they would. But, you know, in some crazy way, I mean, even that very first observation, you could actually constrain, for example, the mass of the putative graviton. The truth is we don’t have very good constraints, so, scientifically, that is an important thing to do. But we also don’t have a very good theory for what we should expect.
And, so, but that’s OK, you know. That’s how science marches ahead. Sometimes, the theory guides the experiments. Sometimes, the experimental observations guide the theory, and, so, I think it could go in that direction.
I’d like to ask a very broad question on your perspective on the awards that LIGO received. So, as we both know, Rai, first among many, went to extraordinary lengths to share the Nobel Prize, and to indicate to the whole world that LIGO was not a three-man effort, that there were thousands of people that made this possible. I wonder if you can provide some perspective on to what extent the Breakthrough Prize is a more—it’s a more effective way of conveying big science in the 21st century in a way that the Nobel Prize, which insists on continuing to recognize individuals, does not. Alternatively, is there something objective or subjective, I should say, that Kip and Barry and Rai really should be recognized for their contributions as being singular, above and beyond all of the people who contributed to LIGO? I wonder if you could just share your perspective on all of these ideas.
Yeah, yeah. So, let me start with the last question first. So, I think in terms of if you had to single out individuals, I think that those were a good choice, OK. And I do believe that in—even in something like LIGO where literally hundreds of scientists were involved over decades, scientists, engineers, and, you know, support staff, everyone, I do think that their roles were singular, and in part because they had a vision that got it all started, you know. And they had a vision, they had this incredible tenacity to pursue that vision, and they did something else, which is they kind of convinced the scientific community in the United States at a time when there was a lot of skepticism about LIGO and whether it would ever work. So, I do think they had a singular role to play. And that role is not just in defining the science, because that was done by more than them, but their role in sort of defining the field and the mission. And I think, so, that’s important.
The Nobel Prizes, as we know in so many different ways, are deeply flawed. It cannot be a pure statistical accident that women don’t get recognized, that scientists of color, scientists from anything but the leading nations don’t get recognized. So, I think the Nobel Prize is flawed, even if you look at the selections that are made in some fields where some people are deliberatively left out, you know, against what the community’s wisdom is on that. So, Nobel Prizes are flawed.
In the case of LIGO, given that they choose to be within the constraints of recognizing individuals, this was a good choice. Now, the Breakthrough Prize, on the other hand, I think, you know, it’s so interesting you should ask me this question because I’ve met Yuri Milner only once, and one of the things that I did say to him was that I think that recognizing large collaborations makes it a true 21st century prize. And that is the direction of modern science.
It’s not just big physics experiments. More and more, as scientific fields mature, all the low-hanging fruit gets picked, and then individual efforts are just less effective, and you have to go to larger and larger collaborative teams. So, I think that’s a direction in which science is going in all fields, and the Breakthrough Prize is keeping up with that. I think people sometimes say, “Well, you know, is it really meaningful if 1,000 people in one shot win a prize?” And I think if their contributions to a result were important then, absolutely, it’s meaningful.
For better or worse, the Nobel Prize has a cache that puts it obviously in a league unto itself in terms of scientific prizes. I’ve heard it commented that even if there is something basically flawed about recognizing individuals, from a public policy perspective, from a public relations perspective, given that these are tax dollars that ultimately fund these projects, the people need to see an individual. It’s much more—it’s much easier for the broader public to relate to a face, to an individual, particularly when that face is the smiling face of Rai Weiss, than it would be for a team. I wonder if that comment resonates with you at all.
I think that’s to some part true. But I think, you know, it comes at a price that we should not be willing to pay because in recognizing individuals, historically, we recognize only white men, and that leaves out a huge part of the population that’s looking out there to be inspired by people that look more like them. And, so, I think we are also perpetuating historical inequities when we make those choices, and we have to strike the right balance.
You could imagine processes by which large scientific collaborations still have a leadership, still have spokespersons, and so on. And so those can still be the face of the collaboration. But to know that this whole group of scientists that included these young people, the students, the postdocs, without whom we wouldn’t get this done, I think it’s really important for people to be able to see that a vast and diverse group of people—diverse by scientific standards – made these important scientific discoveries. Look, we’re not that diverse in any case. You know, we have a lot of work to do there—but, you know, achieved these things, and not just the historically celebrated white men.
Nergis, I’d like to return to a very important point you made in our previous discussion where you pushed back against this idea that the success of LIGO should be understood in a binary term, otherwise detection, success, no detection, not success. And you emphasized all of the tremendous advances in basic science that happened just as a result of learning how to build these detectors. So, I’ll just give you an example as I come to appreciate these things, Frances Hellman, for example, her work, you know, amorphous solids, and the mirror coding that really might make LIGO go farther than it’s ever gone before.
I wonder if you can talk a little bit about—further develop this idea that the collaboration itself is not just one of people who understand a lot about gravity. That it’s so much more than that, and that it’s so much more than defining it in terms of success or not success with the detection. I wonder if you can develop that a little more.
I think the last time when we talked, what I had pointed out was that whether or not we ever detected a gravitational wave, we had invented precision measurement techniques that were used in other areas, and the influences of other areas were also a part of the arsenal of technologies we use in LIGO. You brought up the idea of thinking about molecular dynamics [laugh] and amorphous material, really very important.
Some of the opto-mechanical interactions, which is the interaction of light and matter, LIGO, you know, occupies a very unique niche, which is we have a megawatt of laser light shining on kilogram-scale mirrors. When you normally think of light–matter interactions, you think about light with atoms. People have been thinking about light now interacting with motion at the nanoscale, things like that.
I mean, we do it on a completely different scale, right, which is human-scale objects. But the same light–mirror interactions that we rely on to make a very precise measurement in LIGO can also be used to study quantum effects on human-scale objects. And this is an area that, you know, is quantum mechanics—one of the biggest, hottest areas of physics right now; and it’s being thought of in part because of all the ideas to do with quantum information systems, and quantum sensing. And here is an instrument that was designed to detect gravitational waves that actually has something to say about fundamental quantum mechanics, but on a scale that no one thinks quantum mechanics is important on, right—
—the human scale. And so I think you have to keep coming back to this idea that when you further, human technology, technical capability, through a goal—I think these things we developed for LIGO would not have happened if we didn’t have this goal that there’s these faint gravitational waves out there, and the only way we can measure them is if we have this precision. So, that goal was really, really important. But achieving the goal may not have been so important for developing those technologies.
On the question of the subfields that advanced LIGO and conversely how LIGO advanced those subfields, specifically with laser cooling, how does that interplay? How is that played out?
Yeah, so, this is related to the opto-mechanical system that I just talked about. Typically, when you want to cool down atoms, one of the significant techniques that is used is optical cooling and trapping, and that’s really, again, it’s to do with the interaction of how atoms absorb light or—and give off light. And that process of absorbing a photon, and then emitting a photon can put an atom into a lower energetic state, cool it. And you can actually do similar things for mechanical objects like mirrors, and that’s part of the techniques that kind of sprouted out of LIGO.
To be clear, cooling and trapping a mirror doesn’t necessarily make LIGO better, because, in the end, to make a gravitational wave measurement, you want a mirror that’s free to move and respond to the gravitational wave, and trapping it doesn’t do that. But what it does do is, by using these ideas and applying them to LIGO allows you to study quantum mechanics on this very large scale. So, that’s part of why the cooling and trapping work that’s come out of my group has been so exciting.
It came out squarely out of thinking about the precision of LIGO, and how to improve that precision, but it has this whole other life, which is it’s really answering a different question. It’s not answering the question of gravitational wave detection. It’s answering the question of things like, “Is there a scale on which quantum mechanics doesn’t work anymore?” And people have not known how to answer that question because quantum mechanics was invented for the microscopic.
But then where does it break down? Does it break down at a nanoscale? Does it break down at a microscale? Does it break down at a kilo scale? And I say “scale” without any units because, you know, it could be mass, it could be distance. And, so, you could start asking those kinds of questions. Another really interesting question you could ask is, when you take an object like a ball or a person, you know, one of us, you don’t need quantum mechanics to describe our motion, and the question is “Why? What’s so special about atoms or smaller objects?” And, in the end, there’s nothing special. In the end, the only reason that’s true is that at this macroscopic scale, our motion is dominated by our thermal energy.
So, if you could cool us down, if you could cool me down to nanokelvin [laugh], I, too, would have to be described by quantum mechanics. I don’t want that to happen because I won’t live to tell the tale, but you know what I mean. And, so, those are the kinds of questions you can start to ask, and you can say these are really fundamental questions of physics. This is one of the things I really love about this field. The interplay between technologies that enabled the detection of gravitational waves are some of the same technologies that will enable us to answer these fundamental questions in physics. And why? There’s one answer: precision.
Yes. I’ll just note editorially that, again, from the public relations perspective, this is such an extraordinarily important point because the next time the NSF thinks about what it wants to spend a billion dollars on, it should not think of these things in binaries of success or failure; that what LIGO demonstrates is that there’s a tremendous amount of basic science value that comes just in the course of doing this kind of experiment. So, that’s—it’s a really—
I think that is really important. You’re right. And I think part of that has to be educating the taxpayers and the government officials that fund these projects, because I think within the NSF, there is a lot of understanding and appreciation for research that will lead to good outcomes, but not necessarily the known outcomes, or the outcomes that we think of going into it. But that’s a lot harder to convince people outside of the scientific enterprise of. But it’s an important story to be told.
Let’s move over to the administrative side of things when in 2015, you’re named associate head of the department of physics. So, the first thing just to state there so people understand why the department needs an associate head, it’s because it is an enormous department. I think it’s the largest physics department in the country, if not the world. I’m not sure how to count that exactly. But, whatever it is, it’s a very big department. So, the first question there is, what were the circumstances of you being asked to take on this responsibility?
Yes, it is a very big department. I’m not sure how it compares to the world. But, certainly, I think, within the U.S., it’s among the very biggest departments, both in terms of the number of faculty and the research volume, but also students. So, yeah, so it’s a big job for just one person, the department head. The way that came about was that a new department head was named. And I had been at the time, for a few years already, been serving as the undergraduate officer. So, my job was to sort of really look out for undergraduate issues, everything from advising to well-being to academics. And, so, the new department head, Peter Fisher, who in the meantime has become a dear friend and colleague, asked if I would be the associate head.
When I was having conversations with colleagues about whether to do this or not, Advanced LIGO—this was before the discovery—and Advanced LIGO was about to come on the air, and our quantum systems were going to be the next thing in line, and so, you know, my group was also working on that. And, so, I had to think hard about how to balance out the competing demands, because I did really feel like, and then talking with Peter, I did really feel like I could play a meaningful role, and I would have something to contribute to the department as well. [laugh]
But, at the same time, there was no time in the day. And, so, that took a bit of thinking. But, you know, in the end, the compromise that I made, and—I wonder about that because it wasn’t easy—the agreement we came to was that in order for me to keep my research going, and to be the associate head, something had to give, and so I got a significant amount of teaching relief for doing that. And then that’s bittersweet because I actually love teaching, and I love the interaction with students, etc. Now, I may not say that—
What are your favorite classes, Nergis, to teach? What do you love to teach the most to undergraduates?
I’ve taught a number of classes that are, you know, first-year, second-year, and third-year undergraduate classes, including a very significant lab class that’s offered in the physics department at MIT. And they’re all very different, and I’ve loved them all. I wouldn’t say I love teaching the night before when I’m frantically preparing the lecture. But, you know, when you step back, on the whole, I really have enjoyed it.
So, I understood that I was giving up something that I enjoyed, but I also felt like I had something to contribute to the department, and that sort of led me down that path. And I think it was a good path, you know. I think the partnership with Peter was really great in the sense that I had a lot of room to experiment and grow, and he was very supportive of my work and my ideas, and that really makes a difference.
What opportunities did you see in this role to improve the tone in the department with regard to diversity, with regard to inclusivity?
This is an area, a topic that has gotten a lot of attention in the past year, but our work has been going on much longer than that. It precedes me by a lot too. In fact, the department head previous to Peter Fisher was Ed Bertschinger, and one of the things that Ed really dedicated an enormous amount of his sort of efforts as department head to was increasing the diversity in the department, and really also trying to create a more inclusive environment. It’s been a very difficult problem to get results on, but it hasn’t been for the lack of trying. So, you know, when I went into that, I kind of knew that that was also one of our priorities.
When did it first become apparent that you would take on this major step up to dean?
Oh [laugh], not at all apparent [laugh]. You know, I’m still amazed that [laugh], you know, here I am being dean. So, a few things. When the former dean was stepping down, I had not thought at all about myself in the role of the dean. But as is common in the search committee process, I was contacted by members of the search committee just asking for general thoughts on what the qualities the dean should be. And I kind of wrote them down, and I sent them back. And I had—you know, I hadn’t ever thought of myself in the role, but I did have a conversation with my department head, Peter.
I’m going to sort of deviate into another area that we haven’t touched upon, which is mentoring. One of the very important foundations of my entire career has been that I have always found people who were there to support me and mentor me. And I think Peter was one of those people. He was always looking out for ways in which I could grow. And so, we talked about the dean’s position. He was the department head, and there were other department heads who would be natural candidates. And, so, when the search committee approached me to be considered for this, I was very surprised. But then I was also surprised by another thing.
I was surprised by how it didn’t scare me [laugh], and maybe that’s a terrible thing. [laugh] Maybe I should be scared of this. I kind of felt like, “Oh, my goodness; I have so little idea of the job and, yet, I think I could contribute.” And, so, it was kind of a sort of a mixture of, yeah, maybe some—a lot of trepidation, and also, of, I’m concerned that, you know, I had not yet been a department head, and therefore had a lot of learning to do. And, of course, also I certainly did not want to be [laugh] dean if my friend and colleague, my department head was going to do so.
But, again, Peter was not interested in the job, and that made it a little bit easier for me to think about whether it could be me. So, yeah, here I am. But I have to say—that was not where I thought I would be [laugh]. I had thought certainly about administrative roles because I was the associate head, and, interestingly enough, you know, when the pandemic hit, it was—like, I’ve never experienced a time like that in my career. And, you know, that’s saying a lot because, you know, I was alive through the detection of gravitational waves [laugh] and all of that.
The pandemic was a time where we’ve never worked so hard. But I also have to say we were incredibly innovative. So much was coming at us. We were solving problems in a very unscientific way, if you like, because there was no time to experiment and analyze data as we’re used to doing. It was – everything was happening faster than we could do that. And I actually found that to be really important training for the dean’s job where things come at you very fast. So, the pandemic, painful as it’s been, also was a time of real, I would say, creativity and innovation—
—as you were considering this dean position, was there a point at which the excitement over LIGO—I don’t want to say it ever died down. Nothing ever dies down with excitement with LIGO. But, you know, when your research group was more involved with the quantum sensing stuff, was—what were your concerns about where your research group was, and how that might be impacted by taking on the dean role?
That’s a really good question. It’s one of my biggest concerns. My two biggest concerns in taking on the dean’s role was how is this going to impact my family—I have younger kids at home [laugh]—and, you know, and do I need to get even more busy than I am?
And then the second question was really—I’m still filled with ideas and excitement about the research that I’m doing, and so was this a good time to do that? So, I think a few things were important in that decision. So, one of the things that compelled me the most was that I had had this taste for discovery, and I kind of felt like it was time for me to enable that for others. I really felt like everybody who spent a career in science should have something this wonderful happen to them, and if I could play even a small role in that, that would be worth it.
So, that, I think, was a very big motivator that I had had all these successes because some others were doing the work of making it possible, you know, whether openly and acknowledged, like, the mentors that I worked with, or, in the background, whether it was other faculty or staff. So, I kind of just felt like it was time to give back, and this was one of the ways in which I could think of doing so. So, that was a very big part of the motivation for me to do this. And the second piece of it was I felt like, given the imperatives to do more for diversity and inclusion, it was time for me to step up. There was some sense of maybe duty, but in a good way. I wasn’t cornered into doing it, by any means. I felt like I could make a difference, and so it was time for me to do so.
And then you asked about how does that jibe with the research? Well, it’s been harder on my group. You know, between the pandemic and my stepping up to be dean, it’s been harder. But there’s a piece of me that still so enjoys the research—I do make time for it. And, so, I think right now, 20% of my time is spent on research. And in the summer, that will go up.
Oh, that’s great.
So, I’m really excited about that.
That’s great. And that’ll keep you happy. That’s 20% happy time for you, right?
Yeah. Yeah, I know. You know, I would say with everything that comes at me, you know, my only regret in life is that there isn’t more hours in a day.
Like, I don’t want less to do. I just want more time—
—to be able to do it.
[laugh] That’s great. That’s great. Nergis, for the last part of our talk, now that we’ve worked right up to the present, I’ll ask one retrospective question, we’ll talk in the moment, and then we’ll look to the future. So, my retrospective question is I want to return to that amazing exchange you shared with me when you came to Rai Weiss, and he said, “I don’t give a rat’s ass about what classes you took,” and you sort of panicked in the moment, and said, “I know how to fix bicycles,” right?
I’d like to ask you to reflect on your mechanical engineering sensibilities, and how that has served you so well over the course of your career.
I think that’s a good question. Part of why I feel like the universe dumped me in just the exact right place is that I love working with my hands, and being an experimental physicist allowed me to do that. And, in some ways, it wasn’t just mechanical engineering, which bicycles was, it was also electronics and electronic design. So, I loved that piece of it.
And one of the things that I’ve really also appreciated about being part of the early days of LIGO, and even now, actually, it’s true—I might have said this to you before, but I’ll say it again because it’s so meaningful—when you are trying to do something of the precision that LIGO was trying to do, and sort of pushing the state of the art so much further than it was, you can’t buy things. You have to really design and invent things for yourself. And, so, that really landed me in the right place because I love that part of the work but I also really love thinking about the physical universe and the question of “Where do we come from?” and the more fundamental questions. So, it was kind of the perfect match for me where I could use engineering practices and day-to-day sort of work. But it was really answering more fundamental physics questions, which I also really loved. So, that, I would say, is part of the passion.
To return to one of my earliest questions, you took on the dean role when COVID was already a long-term proposition. You didn’t become dean in February of last year when this may have been like a month or something like that. So, long-term, what do you think are the best opportunities to operationalize the positive response, the innovation, the way that people have been creative, figuring out how to keep the science going? As you look forward to your future tenure and your goals as dean, what might you learn from this year-plus experience that might make MIT science even stronger than it was?
Yeah, that’s a really good question. Answering that question is still a work in progress—very much so. But I feel if you look at what did we get done, it’s very easy to think about, “Oh, we had this tremendous response to the pandemic, to COVID.” You know, in less than a year, science invented a vaccine, etc. You know, there’s an important subtlety to that. None of that happened in this year. This was science that we had done in the 1970s and 1980s—
—that was coming into play here. That’s a really important thing. Again, when we think about why we do science, how we fund it, what do we fund—to keep in mind that the discoveries of today may not feel like they’re so significant or have many applications. And, yet, in a decade or two, they could save literally lives. They could save the planet, all of those things. So, that’s the first thing to think about.
The second thing to think about is, this was built on the discoveries of the past decade, this was also a time of great innovation and creativity. And I think part of that comes from this shared goal. People, they had a singular goal, which was: We have this terrible pandemic, and how do we help keep people safe and well in the pandemic?
And, so, I think—well past the pandemic—continuing to define shared goals for humanity will push science forward in this way where people were really collaborative and innovative, etc. And, there’s no shortage of such things. I mean, if you just look at one of the greatest [laugh], crises facing humanity right now, which is climate change and the health of the planet, it’s a huge, an enormous scientific challenge, and there is a scientific challenge.
You know, there’s a lot of thought that, “Well, the science is settled, and now the solutions that we need for climate change are sort of political and policy,” and we certainly need policy and politics, and economics to play in. But the science has a lot to contribute still as well. So, I feel like those are the kinds of things that would take us forward. Now, there’s a twist to that, which is of course people are exhausted. There’s only [laugh] so much energy you can put into this long-term. So, I also think that it would be a mistake to think that this running without a break can be sustained forever. So, I think another important lesson to learn from here is, yes, we had this pandemic, there was this tremendous response, but now people also have to breathe. And, so, you know, building in some natural breathing room is really important as well.
So, those are sort of my top-level thoughts. You know, there’s a lot of details on, “What will the workplace look like in the future? Who’s going to commute? Who’s not?” You know, those kinds of things are important questions to ask as well. And, also, really, I think in higher ed, there are important questions that we were forced into experiments that we wouldn’t have done otherwise, like many universities didn’t require GREs or standardized testing. Many people who are very serious scholars of these have said standardized testing doesn’t meet the goals of higher education. [laugh] Now, we have data.
We will in, you know, in a few years because now we have cohorts of students who have entered colleges and universities without those standardized tests—I’m very excited about that because these are not experiments we would have voluntarily done easily. And, yet, here we have data that we’ll use hopefully meaningfully. So, I’m very optimistic that very good things will come out of this terrible time for humanity.
Nergis, last question, looking to the future, another binary perhaps to push back against is that with the Nobel Prize, with the detection of the gravitational wave, LIGO did what it was there to do, and it could now wrap up shop when, in fact, the opposite is true, that things are really starting to get exciting and interesting now. For you, from your vantage point, from your long relationship with Rai, for understanding this at such a deep scientific level, best-case scenario, what will LIGO teach us about the universe, and when might it teach us that?
I think the “When?” is already happening—and the “Why?” is something we’re learning already, and some things will unfold over the next decades and century. So, let’s be a little bit more specific. So, the very first objects that LIGO observed were 30 solar mass black holes that orbited each other and collided. And, right away, the question comes up, “Well, how does nature make such heavy black holes?” Because this class of stellar mass black holes are usually formed when stars die, and collapse into either neutron stars or black holes.
But we know that except for extremely old stars, which there aren’t very many of them and they’re far away—stars don’t grow to be 30 times the mass of our sun. So, there’s a mystery. “How did nature form these black holes?” Another mystery is “How do these black holes come into orbit around each other?”
They could either be lonely black holes, individual black holes out in space, and they somehow come close enough to each other to gravitationally get bound and start orbiting each other. That seems a little unlikely because, you know, it turns out the universe is big, and it’s actually not very dense. So, the chances that two black holes actually meet each other in general is not very high, unless they live in globular clusters which is a dense collection of stars.
So, there’s all these questions that you can ask. You know, “How does nature form these black holes? How do they come about to be in pairs? What happens at the end of their lifetime? How many are there? How heavy can they get? Are they neutron stars? Are they black holes?” These are just some of the questions we’re already grappling with, just from this handful of, you know, a few dozen discoveries that we’ve made. Now, as instruments get more powerful, there will inevitably be objects that we’ll discover that we didn’t know nature made, and that is going to open up a whole new area of thinking about, you know, of understanding the universe.
And there’s good reason to expect that because every time we’ve turned on a new telescope that looks at a different wavelength of light than we had observed, we discover new objects. So, if the history of observation tells us anything, this will happen for gravitational waves as well. And then, finally, if there’s one piece of astrophysics that excited me more than anything else that gravitational waves could do, I don’t believe LIGO— I don’t believe these interferometric detectors will do this in my lifetime. But if you look at the future of the field, it is to be able to observe, directly observe gravitational waves from the very early universe, from the Big Bang itself.
And that is like nothing else we could do because when we look at the earliest moments of the universe, and you look at it with light, the earliest light that we can see is the cosmic microwave background, and that is the remnant from the time when the universe was about 400,000 years old. Now, if you want to look further back in time to earlier moments in the universe, light can’t do it for you, and the only method we know of that we have any chance of detecting is the gravitational waves that have been streaming to us from the very earliest moments after the Big Bang. So, if we want to know how this universe got started, that’s the one.
That’s the one.
And I would love to see that, you know.
Nergis, it’s been an absolute pleasure spending this time with you. Thank you so much for carving out time from your very busy schedule to do this. The historical record deeply appreciates it, the AIP deeply appreciates it, and your colleagues at MIT will as well, so thank you so much.
Thank you, David.