Gravitational waves

Interview with Savas Dimopoulos, Professor of Physics at Stanford University. The interview begins with Dimopoulos reflecting on how the pandemic has affected his research, and he gives his initial impressions on the g-2 muon anomaly experiment at Fermilab. He discusses the push and pull between theory and experimentation when searching for physics beyond the Standard Model. Dimopoulos then recounts his early childhood in Turkey, where his family was part of the Greek minority. Due to ethnic tensions, he fled with his family to Athens as refugees. Dimopoulos remembers his early exposure to math and physics and being torn between the two. He describes moving to the US at age 18 for his undergraduate studies at University of Houston. Dimopoulos then recounts his inclination toward theory and his acceptance at University of Chicago to pursue his graduate studies under Yoichiro Nambu. He discusses his post-doctoral appointment at Columbia which then led to an offer from Stanford. He explains his research in baryogenesis and technicolor, as well as his brief time at Harvard with Howard Georgi. Dimopoulos talks about his return to Stanford, his work at CERN, and his research on large extra dimensions with Dvali and Arkani-Hamed. He concludes the interview with predictions for the future of physics beyond the Standard Model.

Interview with Barry Barish, Linde Professor of Physics Emeritus at Caltech, where he retains a collaboration with LIGO, and Distinguished Professor of Physics at UC Riverside. Barish recounts his childhood in Los Angeles and emphasizes that sports were more important than academics to him growing up. He explains his decision to attend Berkeley as an undergraduate, where his initial major was engineering before he realized that he really loved physics, and where he was advised by Owen Chamberlain. Barish describes the fundamental work being done at the Radiation Lab and how he learned to work the cyclotron. He explains why Fermi became his life-long hero and why he decided to stay at Berkeley for graduate school, even though the school’s general policy required students to pursue their doctoral work elsewhere. Barish describes his graduate research under the direction of Carl Hemholz, and he explains how he developed a relationship with Richard Feynman which led to his postdoc and ultimately, his faculty appointment at Caltech. He discusses how his interest in neutrinos led to his work at Fermilab and why the big question at the time was how to discover the W boson. Barish describes his key interests in magnetic monopoles and neutrino oscillations, and he describes his involvement with the SSC project through a connection with Maury Tigner at Berkeley, which developed over the course of his collaborations with Sam Ting. He explains that his subsequent work with LIGO never would have happened had the SSC been viable, and he describes his early connection as a young student learning general relativity as a connecting point to LIGO. Barish describes his general awareness of what Rai Weiss had been doing prior to 1994 and he relates the state of affairs of LIGO at that point. He conveys the intensity of his involvement from 1994 to 2005 and he describes the skepticism surrounding the entire endeavor and what success would have looked like without any assurance that the experiment would actually detect gravitational waves. Barish describes the road to detection as one of incremental improvements to the instrumentation achieved over several years, including the fundamental advance of active seismic isolation. He narrates the day of the detection, and he surveys the effect that the Nobel Prize has had on the LIGO collaboration and its future prospects. Barish notes the promise that AI offers for the future of LIGO, and he prognosticates the future viability of the ILC. At the end of the interview Barish explains what LIGO has taught us about the universe, and what questions it will allow us to ask in the future as a result of its success. 

Interview with Peter L. Bender, Senior Research Associate at the University of Colorado and the Joint Institute for Laboratory Astrophysics (JILA) in Boulder. Bender recounts his childhood in New Jersey, he describes his undergraduate focus in math and physics at Rutgers, and he explains his decision to pursue a graduate degree in physics at Princeton to work with Bob Dicke. He discusses his dissertation research on optical pumping of sodium vapor, which was suggested by Dicke as a means of doing precision measurements of atoms. Bender discusses his postdoctoral research at the National Bureau of Standards, where he focused on magnetic fields and he narrates the administrative and national security decisions leading to the creation of JILA in Boulder, where the laboratory would be less vulnerable to nuclear attack. He describes his work on laser distance measurements to the moon and his collaborations with NASA, and he discusses his long-term advisory work for the National Academy of Sciences and the National Research Council. Bender describes the origins of the NASA Astrotech 21 Program and the LISA proposal, he explains his more recent interests in massive black holes, geophysics and earth science, and he explains some of the challenges associated with putting optical clocks in space. At the end of the interview, Bender reflects on the central role of lasers in his research, and he explains the intellectual overlap of his work in astrophysics and earth physics, which literally binds research that is based both in this world and beyond it.

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.

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.

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.

Interview with Steven Weinberg, Jack S. Josey-Welch Foundation Chair in Science and Regental Professor at the University of Texas at Austin. The focus of the interview is on how and when Weinberg became interested in cosmology, and how he defines it as a distinct discipline from astronomy and astrophysics. Weinberg explains that between the intensity of interest in particle physics in the 1950s and the speculative nature of cosmology, he had neither the interest nor the outlet to pursue cosmology in a rigorous way. He discusses some of the theoretical and experimental limitations at the time that kept cosmology in a largely “mystical” realm, and why the discovery of the microwave background by Penzias and Wilson “changed everything.” Weinberg explains what new questions can be considered as a result of evidence for a hot early universe, and he discusses when he first became interested in the formation of galaxies. He describes why the cosmological constant has bothered him for a long time, and he traces this problem back to Einstein and what Weinberg considers Einstein’s incorrect approach to his own theory. Contrasting his own experience as a graduate student, he cites John Preskill as his first student to pursue cosmology, and he explains that while his interests in particle physics and cosmology are generally separate, he always looks for intersecting research opportunities, which is well represented in the relevance of beta decay physics in the first three minutes of the universe. At the end of the interview, Weinberg surveys the value and problems associated with the term “Big Bang,” and he reflects on his career-long effort not to be dogmatic in his views on cosmology.

Interview with Wick Haxton, professor of physics at UC Berkeley. Haxton recounts his childhood in Santa Cruz and his early interests in math and science. He describes his undergraduate education at the newly created UC Santa Cruz where his initial interest was in mathematics before he was given the advice that he did “mathematics like a physicist.” Haxton discusses his graduate work at Stanford where his original intent was to study general relativity before he connected with Dirk Walecka and Bill Donnelly to focus on nuclear theory and dense nuclear matter. He discusses his postdoctoral research at the University of Mainz where he concentrated on photo-pion physics during the early days of chiral perturbation theory, and he explains the opportunities that led to his next appointment at the LAMPF facility at Los Alamos. Haxton emphasizes the excellence of both his colleagues and the computational capacity at the Lab, and he describes his faculty appointment at Purdue and the solar neutrino experiment he contributed to in Colorado. He explains the opportunities that led to him joining the faculty at the University of Washington where the DOE was about to fund the Institute for Nuclear Theory. Haxton explains the “breakup” between nuclear theory and particle theory and how the INT addressed that. Haxton discusses the opportunities afforded at the INT to engage in nuclear astrophysics and he explains the rise and fall of the Homestake DUSEL project. He explains his decision to go emeritus at UW and to join the faculty at UC Berkeley and to be dual hatted at the Berkeley Lab, and he describes his tenure as department chair. At the end of the interview, Haxton describes his current work organizing the new Physics Frontier Center and the challenges presented by the pandemic, and he credits his formative time as Los Alamos for the diverse research agenda he has pursued throughout his career.

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.