Cosmology

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.

The interviewee has not given permission for this interview to be shared at this time. Transcripts will be updated as they become available to the public. For any questions about this policy, please contact [email protected].

Interview with Katherine Freese, Director of the Weinberg Institute for Theoretical Physics, the Jeff and Gail Kodosky Endowed Chair in Physics at UT Austin, and the Director of the Texas Center for Cosmology and Astroparticle Physics (TCCAP). Freese begins the interview with an overview of terminology, such as cosmology, astrophysics, and astroparticle physics and the delineation between these fields. Then she describes her childhood in Bethesda, Maryland where both her parents were scientists. Freese recalls beginning college at age 16, starting at MIT and then transferring to Princeton. She recounts taking time off after her undergraduate studies, before deciding to pursue graduate studies. Freese began grad school at Columbia but switched to the University of Chicago to work on neutrino physics with David Schramm. She discusses her first post-doc at Harvard, working on WIMPs and dark matter, and then her second post-doc at Santa Barbara with Frank Wilczek. Freese then recalls returning to MIT as a professor where she worked with Alan Guth and Josh Frieman on cosmic inflation. She talks about her transition to the University of Michigan and the exciting developments in cosmology at the time, as well as her introduction to dark energy. Freese describes her more recent involvement with NASA’s SPIDER experiment, as well as the honor of being named to the National Academy of Sciences. Freese discusses the amazing opportunity of being the Director at the Nordic Institute for Theoretical Physics and ends the interview with her hopes for the future of cosmology, namely her hope for finding dark matter.

The interviewee has not given permission for this interview to be shared at this time. Transcripts will be updated as they become available to the public. For any questions about this policy, please contact [email protected].

In this interview, Paul Schechter, the William A. M. Burden Professor of Astrophysics, Emeritus, at MIT discusses his time as an undergraduate student at Cornell University under the mentorship of Al Silverman and his involvement working on the Cornell synchrotron, as well as Silverman’s influence on his decision to attend Caltech for graduate school. Schechter discusses his collaboration with Bill Press on the issue of dark matter and the eventual creation of their model, the Extended Press-Schechter. He also details how studying the infall of galaxies toward the Virgo Cluster, and the subsequent paper he contributed to on the topic, were the most exciting part of his time working at the Kitt Peak National Observatory. Schechter describes his later interests in gravitational lensing and his efforts to create higher quality images for Magellan telescopes. Lastly, he discusses his desire to find the stellar mass fraction in galaxies.

Interview with Brian Schmidt, Distinguished Professor and Vice Chancellor and President of the Australian National University. Schmidt surveys the Covid crisis from his perspective at ANU, and he describes his current interests in cosmology. He recounts his childhood in Montana and Alaska in support of his father’s career in fisheries biology, and he describes his undergraduate education as a dual major in physics and astronomy at the University of Arizona. Schmidt describes the opportunities that led to his graduate work at Harvard, where he worked under the direction of Bob Kirshner and where he met and developed a formative relationship with Adam Riess on supernovae research. He explains his decision to remain at Harvard for his postdoctoral research and he narrates the origins of the High-Z collaboration and its interactions with Saul Perlmutter’s team at Berkeley. Schmidt describes his postdoctoral appointment at ANU as leader of High-Z, and he describes how the collaboration discovered the accelerating expansion of the universe and the process of communicating its findings. He describes the “buzz” leading to the Nobel Prize and his subsequent focus on the SkyMapper project. Schmidt discusses his responsibilities as Vice Chancellor which overlap strongly with Australian national policy, and he describes how he sees the reality of climate change in his 21 years of grape growing. At the end of the interview, Schmidt reflects on how the High-Z discovery has changed astronomy broadly, and he conveys a sense of wonder at the accidental nature by which the team arrived at its discovery.

In this interview, Andreas Albrecht, Distinguished Professor of Physics and Director of the Center for Quantum Mathematics and Physics (QMAP) at the University of California, Davis, discusses his life and career. Albrecht describes the growth of the department since his arrival, his affiliation with QMAP, and the broader effort to integrate more mathematicians into the field of cosmology. He recounts his childhood in Ithaca as the son of two PhD scientists and family sabbatical visits to Santa Cruz and to the Soviet Union. Albrecht describes his budding interests in physics in high school, his undergraduate experience at Cornell and his early exposure to the ideas of Robert Dicke and Alan Guth. He discusses his graduate work at Penn and the circumstances that led him to become Paul Steinhardt’s mentee in cosmology. Albrecht conveys all of the excitement surrounding inflationary cosmology in the early-mid 1980s and the opportunity that led to his postdoctoral appointment with Steve Weinberg’s group at the University of Texas where he became interested in cosmic strings. He describes his subsequent postdoctoral appointment at Los Alamos where he worked with Wojciech Zurek and where his carpools with Geoffrey West proved to be a formative intellectual experience. Albrecht explains his decision to accept a staff position at Fermilab and the contemporary advances in cosmic strings scaling and why primordial nucleosynthesis was uniquely data-oriented relative to other fields in cosmology. He describes his subsequent faculty position at Imperial College in London and he emphasizes the productive and tight-knit cosmology community across the UK. Albrecht conveys the importance of the cosmic microwave background (CMB) experiments and how his ideas of equilibrium cosmology had changed over time and where the term “Boltzman Brains” originated. He describes how UC Davis was rapidly growing and how the opportunity to build a cosmology group was appealing to him. Albrecht explains the origins of his “arrow of time” concept and why this resonates with the broader public’s interests in the universe. He conveys the existential difficulty, and possible impossibility, of developing a credible theory of the beginning of the universe. Albrecht reflects on the spiritual dimensions of cosmological unknowability and the significance of the anthropic principle, and he discusses his efforts as department chair to enhance diversity in the field. At the end of the interview, Albrecht discusses his current work on decoherence and einselection, and he explains why avoiding prejudices in one’s scientific sensibilities is both singularly difficult and key to unlocking future discovery.    

In this interview, Robert P. Kirshner, Clowes Research Professor of Science at Harvard University, discusses his interests in supernovae and work as Chief Program Officer for Science at the Gordon and Betty Moore Foundation. He reflects upon the shifting terminology pertaining to astronomy, astrophysics and cosmology. He discusses his experience as an undergraduate at Harvard University. Kirshner details his experience at Caltech as a graduate student and his time studying supernovae under Bev Oke. He discusses his post-doc position at Kitt Peak National Observatory and the competition they had with Palomar. Kirshner speaks about his experience working with undergraduate students at the University of Michigan and eventually becoming the chair and observatory director. He details his role as head of Optical Infrared at the Harvard Smithsonian Center. Lastly, Kirshner discusses his Nobel Prize winning discovery of using observations of distant supernovae to discover the accelerating universe.

In this interview, Michael Peskin discusses: his childhood in Philadelphia; Alan Luther; particle physics at Cornell; relationship with David Politzer; Leonard Susskind; reactions to Gabriele Veneziano’s string theory paper; overview of Ken Wilson’s career and publications; Thirring model; the Harvard Society of Fellows; Nambu-Jona-Lasinio model; quark confinement work; thinking Beyond-the-Standard-Model (BSM); the problem of electroweak symmetry breakage; Stanley Brodsky and Peter Lepage; work on technicolor models to try to explain the quark and lepton mass spectrum; involvement in discussions around the Superconducting Super Collider (SSC); interest in e+e- colliders; collaboration with Bryan Lynn; question of the mass of the top quark; developing the Introduction to Quantum Field Theory textbook with Daniel Schroeder; impact of the collapse of the SSC on physics research; involvement in planning discussions for the International Linear Collider (ILC); movement into cosmology and astrophysics; dark sector theories; reaction to the term “God particle;” discussion of his book Concepts of Elementary Particle Physics; explanations of various views of the top quark; experiences working with Stanford graduate students; changes at SLAC and its contributions to the field; topics in string theory; AdS/CFT duality; BaBar and Belle experiments and CP violation; current work on electroweak symmetry breaking in Randall-Sundrum models; ILC as the future of high energy physics and physics BSM; China’s proposed Circular Electron Positron Collider (CEPC); technical details of proposed Future Circular Collider (FCC); plasma wake field accelerators; work on particle physics website for Michael Cooke of the DOE; and the technological contributions of particle physics, especially in regards to informatics development, machine learning, and unique sensor development. Toward the end of the interview, Peskin reflects on the utility and limitations of the Standard Model, and details the most likely opportunities for discovery, especially those made possible through the construction of an e+e- collider.

In this interview, Jo Dunkley, professor of physics and astrophysical sciences at Princeton, discusses her life and career. Dunkley describes the nature of this dual appointment and she recounts her childhood in London and her all-girls school education. She describes her undergraduate experience at Cambridge and the formative influence of Malcolm Longair’s class on relativity. Dunkley explains that pursuing a graduate degree in physics was not a foregone conclusion, and that she initially considered a career in international development. She discusses her motivation to study under the direction Pedro Ferreira at Oxford to work on the cosmic microwave background experiments. Dunkley conveys the immediate importance of Wilkinson Microwave Anisotropy Probe (WMAP) on her thesis research and the opportunities that led to her postdoctoral work at Princeton to work with David Spergel and Lyman Page on WMAP. She explains her decision to return to the Oxford faculty to continue working with Ferreira and the origins of her involvement in the Atacama Cosmology Telescope project and subsequently the Large Synoptic Survey Telescope (LSST, now the Vera C. Rubin Observatory) endeavor and her work on it with Ian Shipsey. Dunkley discusses the challenges in maintaining a work-life balance during maternity leaves at Oxford and then at Princeton, after she joined the faculty in 2016. She describes the many exciting projects her graduate students are working on and she explains her current interests in understanding the Hubble constant. At the end of the interview, Dunkley surveys the major unanswered questions in contemporary cosmology, the viability of discovering the mass of neutrinos, and what the interplay between theory and experimentation might hold for the future.