Bulletin of the American Physical Society
APS April Meeting 2023
Volume 68, Number 6
Minneapolis, Minnesota (Apr 15-18)
Virtual (Apr 24-26); Time Zone: Central Time
Session C07: History of Neutrinos, Cosmology, and Dirac's Algebra |
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Sponsoring Units: FHP Chair: Douglas Stone, Yale University Room: MG Salon G - 3rd Floor |
Saturday, April 15, 2023 1:30PM - 1:54PM |
C07.00001: Anisotropic Cosmologies: From a Slow Start in the 1920s to an Explosion of Interest in the 1950s and Beyond Paul H Halpern In 1921, Edward Kasner published the first anisotropic exact solution to Einstein's field equations of general relativity. As a vacuum solution, Kasner did not imply it was physically realistic. Three decades passed before Abraham Taub published a richer picture of exact solutions, aimed at investigating Mach's Principle. That work, and the goal of resolving the horizon problem helped inspire Charles Misner to propose the Mixmaster Universe, around the same time as the Belinski–Khalatnikov–Lifshitz singularity research, each focused on the Bianchi type IX anisotropic cosmology. We will examine the factors that led to the 30 year gap between Kasner and Taub's work, and the subsequent explosion of interest in such models with the aim of investigating the nature of the initial cosmological singularity. |
Saturday, April 15, 2023 1:54PM - 2:18PM |
C07.00002: Is Dirac's algebra Dirac's algebra? Donald C Salisbury Paul Dirac had definitely contemplated quantum operators at unequal times prior to his 1948 paper on the quantum theory of localizable systems. And although he did at times cite related work of others, he seldom referred to inspirational conversations. There does exist evidence, discovered by Yin Xiaodong, that he had had significant interchanges with T S Chang at the Institute for Advanced Study in Princeton over a six month period beginning in the Fall of 1947, and this was concerned with the quantum algebra that arose when altering an arbitrary spacelike surface in Minkowski space. In the context of general relativity this metric-dependent algebra will have a profound impact on an eventual quantum gravitational theory. I will sketch its development, beginning with the work of Paul Weiss and focusing in particular on an interpretation forwarded by Peter Bergmann in 1962. |
Saturday, April 15, 2023 2:18PM - 2:42PM |
C07.00003: An invoice for a hole in the desert, a matchbox full of neutrinos, and other rediscovered artifacts from the hunt for the Ghost Particle James R Riordon, Alan A Chodos A recently uncovered cache of materials that neutrino pioneers Clyde Cowan and Fred Reines collected includes a variety of artifacts that haven’t been seen in over a half century. Notes, images, and invoices offer an intimate glimpse of the efforts that led to first direct detection of neutrinos. The items illuminate key moments in the early history of the hunt for the ghostly particle that Wolfgang Pauli initially proposed as an effectively undetectable entity to explain the seemingly inscrutable spectrum of energy in beta decay experiments. I will present a selection of the newly rediscovered materials that we relied on in writing a new book about the elusive neutrino. |
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