Laser Interferometer Gravitational-Wave Observatory (LIGO)

Interviewed by
David Zierler
Interview date
Location
Video conference
Abstract

In this interview, David Zierler, Oral Historian for AIP, interviews Peter Fritschel, Senior Research Scientist in the Kavli Institute for Astrophysics at MIT. Fritshel explains the historical connections between Kavli, Caltech, MIT, and the overall LIGO collaboration. He recounts his childhood in South Dakota, then New York City, and then back to South Dakota in support of his father’s academic career. Fritschel discusses his undergraduate education at Swarthmore, where he pursued degrees in physics and engineering, and he discusses his post-college work at Raytheon on CO2 lasers in its research division. He describes the events leading to his admission to MIT for graduate school where he joined Rai Weiss’s research lab, and he explains the progress that the lab had made on interferometers at that point in the mid-1980s. Fritschel explains the utility of his background in lasers for Weiss’s lab, and the significance of Caltech’s involvement in the LIGO project. He discusses the relationship between his thesis research on making an interferometer with a power recycling configuration in two arms, and LIGO. Fritschel describes his intent to leave MIT after he defended, and he considered opportunities more broadly in atomic, molecular, and optical physics, which led to his work in Orsay, France, with Alain Brillet and Adelberto Giazotto, the founders of the Virgo collaboration. He explains his decision to return to MIT, and how his work in France was useful for his return to LIGO. He explains how LIGO had advanced during his absence, he discusses his contributions to improving the sensitivity of the gravitational interferometers, and he describes how LIGO had made consistent progress over many years and not “all at once” with the detection of gravitational waves in 2015. Fritschel explains that the Nobel Prize given to LIGO’s principal scientists recognized the collaboration both as a theoretical and an experimental endeavor, and he describes the overall positive impact that this recognition had on the collaboration as it continues to push discovery in gravitational wave research and the advances in both physics and engineering that are required for LIGO to realize its future goals. At the end of the interview, Fritschel conveys the centrality of LIGO’s study of black holes and neutron stars in order to harness the collaboration’s ability to garner new insights on the early Universe.

Interviewed by
David Zierler
Interview date
Location
Video conference
Abstract

Interview with Surjeet Rajendran, Associate Professor of Physics at Johns Hopkins University. He provides an overview of his current research activities with David Kaplan in black hole physics, new short distance forces, and modifications of quantum mechanics, and he shares his reaction on the recent g-2 muon anomaly at Fermilab. Rajendran explains why he identifies as a “speculator” in physics, he recounts his childhood in Chennai, India, and he discusses his grandparents’ communist activism, his Jesuit schooling, and how science offered a refuge for rebellion from these influences. He explains his decision to transfer from the Indian Institute of Technology to Caltech as an undergraduate, where he worked with Alan Weinstein on LIGO. Rajendran discusses his graduate research at Stanford, where KIPAC had just started, and where Savas Dimopoulos supervised his work on PPN parameters and solving the seismic noise problem on atom interferometers for LIGO. He describes his postdoctoral work, first at MIT and then at Johns Hopkins, when he began to collaborate with Kaplan on axion detection and the electroweak hierarchy problem. Rajendran explains the rise and fall of the BICEP project, and his Simons Foundation supported work on CASPEr. He discusses his interest in bouncing cosmology and firewalls in general relativity, and he conveys optimism that LIGO will advance our understanding of black hole information. At the end of the interview, Rajendran reviews his current interests in the Mössbauer effect, and explains how nice it was to win the New Horizons in Physics prize, and he prognosticates on how the interplay between observational and theoretical cosmology will continue to evolve and perhaps resolve fundamental and outstanding questions in the field.

Interviewed by
David Zierler
Interview dates
June 7, 14, 21 & 28, 2020
Location
Video conference
Abstract

Interview with Rainer Weiss, professor emeritus of physics at MIT. Weiss recounts his family history in pre-war Europe and the circumstances of his parents' marriage. He describes his childhood in New York City, and he explains his interests in experimenting and tinkering from an early age. Weiss explains the circumstances leading to his undergraduate study at MIT and his original plan to study electrical engineering before focusing on physics. He recounts his long and deep relationship with Jerrold Zacharias, who singularly championed Weiss's interests over the years. He discusses his graduate work on the hyperfine structure of hydrogen fluoride. Weiss describes his formative work with Bob Dicke at Princeton, and he explains how technological advances was beginning to offer new advances in general relativity. He explains how Dicke's influence served as an intellectual underpinning for the creation and success of LIGO. Weiss emphasizes the importance of Richard Isaacson as one of the founding heroes of LIGO, and he describes the fundamental importance of joining his research institutionally with Caltech. He describes his early research with John Mather, and the numerous administrative challenges in working with the NSF throughout the LIGO endeavor. Weiss describes the geographical decisions that went into building LIGO, the various episodes when LIGO's ongoing viability was in doubt, and how both Barry Barish and Kip Thorne contributed to ensuring its success. At the end of the interview, Weiss describes some of the sensitivities regarding who has been recognized in LIGO and who has not, in light of all the attention conferred by the Nobel prize, and he reflects on how LIGO will continue to push discoveries forward on the nature and origins of the universe.

Interviewed by
David Zierler
Interview dates
July 28, August 18, September 4 & 11, 2020
Location
Video conference
Abstract

Interview with William H. Press, Leslie Suringer Professor in Computer Science and Integrative Biology at the University of Texas at Austin. Press recounts his childhood in Pasadena and the influence of his father Frank Press, who was a prominent geophysicist, Caltech professor, and who would become science advisor to President Jimmy Carter. He describes the impact of Sputnik on his budding interests in science, and he discusses his undergraduate experience at Harvard, where Dan Kleppner, Norman Ramsey, Ed Purcell and Dick McCray were influential in his development, and where he realized he had an aptitude for applying abstract equations to understanding physical reality. Press describes trying his hand with experimentation in Gerald Holton’s high-pressure physics lab, he recounts his involvement in student activism in the late 1960s, and he discusses his involvement in computer hacking in its earliest form. He explains his decision to attend Caltech for graduate school and his interest in studying with Dick Feynman and Kip Thorne. Press describes the opportunity leading to his work at Lawrence Livermore, how he got involved with Thorne’s group of mathematical general relativists, the origins of Thorne’s work on gravitational waves, and his collaborations with Saul Teukolsky and Paul Schechter. He describes the formative influence of Chandrasekhar. Press discusses his first faculty position at Princeton where he joined John Wheeler’s relativity group, and he describes his research interests flowing more toward astrophysics. He explains the opportunities leading to his tenure at Harvard, where he was given separate appointments in physics and astronomy and where he founded theoretical astrophysics within the Center for Astrophysics. Press describes his entrée into science policy work in Washington with the NSF Physics Advisory Committee and then later on the National Academy of Science and the National Research Council, and he explains the origins of his long-term association with the JASON Study Group. He describes his interest in gravitational collapse, Ia supernovae and galaxy formation, and why the study of black holes reinvigorated the field of general relativity. Press describes the singular genius of Freeman Dyson, and he recounts his contributions to nuclear risk reduction in science policy and his service with the Defense Science Board and the Institute for Defense Analyses. He discusses his tenure as chair in Harvard’s Department of Astronomy, his experience with the Numerical Recipes books, and his collaboration with Adam Riess and Robert Kirshner. Press recounts his decision take a position at Los Alamos as Deputy Director to John Browne, he describes his education there in the concept of leadership which he never received in his academic career, and he provides his perspective on the Wen Ho Lee spy case and the existential crisis this caused at the Lab. He describes the Lab’s role in the early days of computational biology and how this field sparked his interest. Press contextualizes this interest within his conscious decision not to stay connected to astrophysics during his time at Los Alamos, and he explains the opportunity leading to him joining UT-Austin where he remains invested in computational biology. He describes his work for the President’s Council of Advisors in Science and Technology during the Obama administration, he describes Obama’s unique interest in science and science policy, and he narrates the difficulties in the transition to the Trump administration. Press reflects on what it means to be a member of the rarified group of scientists who did not win a Nobel Prize but who were advised by and taught scientists who did. At the end of the interview, Press explains that he has always been a dilettante, which has and will continue to inform how he devotes his time to science, service, and policy matter, and he advises young scientists to aspire to mastery in a specific discipline early in their career before branching out to new pursuits.

Interviewed by
David Zierler
Interview date
Location
Video conference
Abstract

Interview with Robert M. Wald, Charles H. Swift Distinguished Service Professor of Physics at the University of Chicago, where he also has appointments with the Kadanoff Center and the Kavli Institute for Cosmological Physics. Wald recounts his childhood in New York, he describes the tragedy of losing his parents in an airplane crash when he very young, and he explains the ongoing legacy of his father Abraham Wald who was a prominent professor of statistics at Columbia. He describes his high school education at Stuyvesant and his decision to pursue a physics degree at Columbia, where he became close with Alan Sachs, who supervised him at Nevis Laboratory. Wald explains his decision to focus on general relativity for graduate school and his interest in working with John Wheeler at Princeton. He describes the excitement surrounding recent advances in approaching astrophysics through relativity, the significance of the discovery of pulsars and the field of black hole uniqueness, and he discusses his postdoctoral research with Charles Misner at the University of Maryland. Wald describes the impact of Saul Teukolsky’s discovery of a variable Weyl tensor component that satisfied a decoupled equation, and he explains the circumstances leading to his faculty position at Chicago, where he was motivated to work with Bob Geroch. He reflects on the experience writing Space, Time, and Gravity, the advances in black hole collapse research, and he explains why he felt the field needed another textbook which motivated him to write General Relativity. Wald discusses his work on the Hawking Effect and his long-term interest in quantum field theory, and he explains the influence of Chandrasekhar on his research. He describes his contributions to the LIGO collaboration, and he explains what is significant about the Event Horizon Telescope’s ability to capture an image of a black hole. Wald explains the state of gravitational radiation research and the accelerating universe, he prognosticates on what advances might allow for a unification of gravity and the Standard Model, and he explains why dark energy is apparently a cosmological constant. At the end of the interview, Wald discusses his recent work on the gravitational memory effect and, looking to the future, he explains his interest to continue working to understand the S-matrix in quantum electrodynamics.

Interviewed by
David Zierler
Interview date
Location
Video conference
Abstract

Interview with Saul Teukolsky, Hans A. Bethe Professor of Physics and Astrophysics at Cornell and Robinson Professor of Theoretical Astrophysics at Caltech. Teukolsky recounts his childhood born in a Jewish family in South Africa, and he explains the tensions between his parents’ politics, who were accepting of apartheid, and his own views which rejected this as a national injustice. He describes his undergraduate education at the University of Witwatersrand and the impact of the Feynman Lectures on his intellectual development. Teukolsky explains his interest in pursuing general relativity for graduate school, and he discusses the circumstances leading to his enrollment at Caltech, where he studied Newman-Penrose equations and perturbations of the Kerr metric under the direction of Kip Thorne. He discusses his year-long postdoctoral research position at Caltech and his subsequent decision to join the faculty at Cornell, where he developed the gravitational theory program. Teukolsky explains the significance of the Hulse-Taylor discovery at Arecibo on general relativity, and he describes the early impact of computers on advancing GR research and specifically on numerical relativity which he worked on with Bill Press. He discusses the rise of computational astrophysics, and he surveys his interests in pedagogical issues in physics and his early involvement in LIGO and the LISA collaboration. At the end of the interview, Teukolsky explains how he has tried to communicate astrophysical concepts to broad audiences, and he expresses optimism that massive advances in computational abilities will continue to drive forward fundamental advances in the field.

Interviewed by
David Zierler
Interview date
Location
Video conference
Abstract

Interview with Henry Tye, professor emeritus of physics at Cornell, and subsequently professor emeritus of physics at Hong Kong University of Science and Technology (HKUST), and currently, Researcher at the Jockey Club Institute for Advanced Study at HKUST. Tye provides a brief history of HKUST, and he offers his views on China’s long-term goals in high energy physics. He recounts his childhood in Hong Kong where his family fled from mainland China during the Communist revolution, and he explains the opportunities that led to his undergraduate admission to Caltech. Tye describes how discussions of the Vietnam War permeated his college experience, and he describes the influence of Gerry Neugebauer on his interest in physics but that cosmology was far from his considerations at that point. He discusses his decision to study at MIT, where Francis Low became his advisor, and how he worked closely with Gabriele Veneziano on the relationship between the Thirring model and bosonic string theory. Tye explains the excitement surrounding the “November Revolution” which was unfolding just as he arrived at the SLAC Theory Group in 1974. He describes the origins of his interests in cosmology, and the source of his collaboration with Alan Guth during his postdoctoral work at Cornell, where he pursued matter-antimatter asymmetry. Tye explains how this collaboration ultimately created the field of inflation and why this addresses fundamental cosmological problems associated with flatness and the horizon. He explains how and why the original theory of inflation was revised by Andrei Linde and Paul Steinhardt, among others, and why he developed a subsequent interest in cosmic superstrings and branes which he recognized would give a perfect model for inflation. Tye describes why he is optimistic that technological advances will make cosmic superstrings a testable proposition, and that collaborations including the Sloan Digital Sky Survey and LIGO/Virgo are positive steps in that direction. He bemoans the dearth of string theorists focused on phenomenological work and why he thinks string theory will solve the quantum gravity problem. Tye describes his decision to join the Cornell faculty, why his notions of a “string landscape” suggest philosophical implications, why the cosmic landscape is central for understanding the wavefunction of the universe, and why both the universe and all multiverses can begin from truly nothing. At the end of the interview, Tye discusses his recent interests on the cosmological constant problem, the KLT relation, and the observations and experiments that are most likely to push cosmology into new and exciting areas of discovery. 

Interviewed by
David Zierler
Interview date
Location
Video conference
Abstract

Interview with Marcelle Soares-Santos, assistant professor of physics at the University of Michigan. Soares-Santos recounts her childhood in Brazil, her early interests in science, and her graduate work in physics at the University of São Paulo. She describes her graduate visit to Fermilab to study galaxy clusters as a way to map the history of the expanding universe, which formed the basis of her thesis research. Soares-Santos discusses her return to Fermilab as a postdoctoral researcher, where she joined the Dark Energy Survey, and she explains how DES is getting us closer to understanding what dark energy is. She describes Fermilab’s broad-scale transition into astrophysics, and she explains the opportunities that led to her faculty appointment first at Brandeis before moving to Michigan. Soares-Santos discusses her current work in gravitational waves, and she prognosticates on what the discovery of dark energy (or energies) will look like. She shares her perspective on recent efforts to improve diversity and inclusivity in STEM. At the end of the interview, Soares-Santos explains why observation is leading theory in the current work of astrophysics and cosmology and why she is optimistic for fundamental advances in the field.

Interviewed by
David Zierler
Interview date
Location
Video conference
Abstract

Interview with William "Bill" Unruh, Professor of Physics and Astronomy at the University of British Columbia, and Hagler Fellow at the Institute for Quantum Science and Engineering at Texas A&M. He credits his mentor John Wheeler for the steady progress of interest and work in general relativity over the decades, and he reflects broadly on the original debates among the relativists and the founders of quantum mechanics. Unruh explains the inability to merge these foundations of physics as the source of his attempts to understand the black hole evaporation as found by Hawking. He recounts his upbringing in Manitoba as part of a Mennonite community and his early interests in Euclidean geometry, and he describes his undergraduate education at the University of Manitoba. Unruh explains his decision to pursue a PhD with Wheeler at Princeton on topology and general relativity, and scattering cross sections of black holes to scalar fields. He describes his postgraduate appointment at Birkbeck College where he worked with Roger Penrose and he narrates the origins of his collaboration with Stephen Fulling and Paul Davies. Unruh discusses his time at Berkeley and then at McMaster and he historicizes the point at which observations made black holes more "real," and he explains his first involvement with decoherence. He explains his involvement with LIGO from its origins and its quantum mechanical nature, and he narrates his reaction of amazement when gravitational waves were detected. Unruh describes the impact of his work in quantum mechanics on computation, and he explains some of the advances that have made observation more relevant to his recent research. At the end of the interview, Unruh describes his efforts to launch a Gravity Archive at UBC, he expresses his frustration with people who insist we do not know quantum mechanics, and he quotes Wheeler, quoting his favorite Grook to convey that he is having fun and wants to learn as much as he can, while he can.

Interviewed by
David Zierler
Interview date
Location
Video conference
Abstract

Interview with Gabriela Gonzalez, Louisiana State University Boyd Professor in the Department of Physics and Astronomy. Gonzalez explains how the pandemic has slowed down data analysis for LIGO, and she recounts her childhood in Cordoba, Argentina. She describes her early interests in science and her physics education as an undergraduate in Cordoba. Gonzalez explains the circumstances that led to her graduate studies at Syracuse University where she studied relativity under the direction of Peter Saulson, and where she first became involved with LIGO. She discusses her postdoctoral appointment at MIT to work in Rai Weiss’s group, and she explains LIGO’s dual goals of detecting gravitational waves and building precision instruments toward that end. Gonzalez explains her decision to join the faculty at Penn State and she describes the site selection that led to the detection facility in Livingston, Louisiana. She describes the necessary redundancy of the LIGO detectors at Livingston and Hanford, Washington, and the importance of “locking” the mirrors on the detectors. Gonzalez describes the overall scene at LIGO in the months up to the detection and the theoretical guidance that improved the likelihood of success. She describes the intensive communication and data analysis to confirm the detection prior to the announcement, and she explains how she felt honored as part of the overall Nobel Prize award and subsequent celebration. Gonzalez describes LIGO’s work in the current post-detection period, and her own focus on diagnostics of the data, and she explains why this work, and the constant concern in missing something important, can be stressful. At the end of the interview, Gonzalez surveys what mysteries LIGO can, and cannot, solve, and she conveys optimism for LIGO’s long-term prospects to continue to push fundamental discovery.