Рет қаралды 1,063
Neutron stars were first posited in the early thirties, and discovered as pulsars in the late sixties; however we are only recently beginning to understand the matter they contain. After a brief mention of neutron star history, I will describe the ongoing development of a consistent picture of the liquid interiors of neutron stars, now driven by ever increasing observations as well as theoretical advances. These include in particular observations of at least three heavy neutron stars of about 2.0 solar masses and higher; ongoing simultaneous inferences of masses and radii of neutron stars by the NICER telescope; and past and future observations of binary neutron star mergers, through gravitational waves as well as across the electromagnetic spectrum. I will also discuss pulsar timing arrays to detect very long wavelength gravitational waves, a remarkable role for neutron stars. Theoretically an understanding is emerging in QCD of how nuclear matter can turn into deconfined quark matter in the interior, and be capable of supporting heavy neutron stars, which I will illustrate with a discussion of modern quark-hadron crossover equations of state.
Gordon Baym graduated from Cornell University (A.B.) in 1956, and from Harvard University (Ph.D.) in 1960, as a student of Julian Schwinger. He then spent two years at the Institut for Teoretisk Fysik in Copenhagen (now the Niels Bohr Institute). After a year at Berkeley, he joined the faculty of the University of Illinois, where he is presently a Research Professor of Physics, Center for Advanced Study Professor Emeritus, and Fisher Distinguished Professor of Engineering Emeritus. He has been a regular participant in the Aspen Center for Physics since 1967. Baym’s interests in physics range from quantum statistical mechanics to matter at low temperatures and under extreme conditions. A pioneer in the study of pulsars and neutron stars, he has been a driver in laboratory studies of density matter via ultrarelativistic heavy ion collisions. His ongoing interests include quark matter, primordial neutrinos and the intersection of low temperature and high energy physics. Baym is a Fellow of the American Academy of Arts and Sciences; and a member of the U.S. National Academy of Sciences and of the American Philosophical Society. He is a recipient of the American Physical Society Hans Bethe Prize and Lars Onsager Prize, the Eugene Feenberg Memorial Medal, and the 2021 American Physical Society Medal for Exceptional Achievement in Research. His continuing service to the physics community lately includes chairing the National Academy of Sciences study of the Electron-Ion Collider.
This colloquium was originally recorded on July 18, 2024 at the Aspen Center for Physics. Our Colloquia series is made by physicists, for physicists.