Bulletin of the American Physical Society
APS April Meeting 2015
Volume 60, Number 4
Saturday–Tuesday, April 11–14, 2015; Baltimore, Maryland
Session W1: Plenary Session III: Probing our Limits of Knowledge |
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Sponsoring Units: APS Chair: Deirdre Shoemaker, Georgia Institute of Technology Room: Holiday 4-6 |
Tuesday, April 14, 2015 8:30AM - 9:06AM |
W1.00001: Status of cosmological parameters from the cosmic microwave background Invited Speaker: Krzysztof Gorski European Space Agency and the Planck Collaboration have recently released data products from the full Planck mission, including all temperature and the initial batch of the polarization data. I will review the highlights of this release, and discuss how the data from Planck and such paramount suborbital experiments as ACT/ACTPol, SPT/SPTPol, and BICEP2/Keck jointly allow us to make impressive advances in cosmology, early Universe physics, and astrophysics. [Preview Abstract] |
Tuesday, April 14, 2015 9:06AM - 9:42AM |
W1.00002: Quantum Gravity and Quantum Cosmology Invited Speaker: James Hartle Our large scale classical universe originates in the small scales of a quantum mechanical big bang. A quantum theory of the big bang is the subject of quantum cosmology. The theory consists of two parts: First, a quantum theory of spacetime geometry coupled to matter - a quantum theory of gravity. Second, a theory of the universe's quantum state. Such a combination predicts probabilities for the different large scale classical spacetimes the universe might have. It thus gives probabilities for what we observe. In particular it gives probabilities for the large scale homogeneity and isotropy, for the number of efolds of inflation, for the fluctuations we measure in the CMB and the distribution of galaxies, and, in a landscape where they can vary, for constants like the cosmological constant. This talk will illustrate how this works in a few simple models based largely (but not exclusively) on semiclassical quantum gravity and the no-boundary wave function of the universe of Hawking and his collaborators. 100 years after its inception Einstein's general relativity has significant implications not only for the very large but also for the very small. [Preview Abstract] |
Tuesday, April 14, 2015 9:42AM - 10:18AM |
W1.00003: Proton - a fascinating relativistic many-body system - remains puzzling Invited Speaker: Haiyan Gao Proton, a fundamental building block of visible matter in the universe, is a facinating relativistic many-body system. It is also nature's best laboratory to study strong interaction and quantum chromodynamics, the theory describing it. Despite decades of studies and many discoveries, proton remains puzzling. While the LHC discovery of the Higgs boson validates the mechanism for some fundamental particles to have masses in Standard Model, Higgs is almost irrelevant to the mass of the proton. The European Muon Collaboration discovered in late 1980s that quarks inside the proton contribute only about a quarter to the total spin of the proton. This discovery generated major theoretical and experimental efforts in the last two decades trying to piece together the total spin of the proton. While the proton spin is becoming less puzzling, another new puzzle about proton developed in the last a few years concerning the ``size'' of the proton. The ultrahigh precise value of the proton charge radius determined from muonic hydrogen Lamb shift measurements is 7-8 smaller than values determined from electron-proton scattering experiments and hydrogen Lamb shift measurements. In this talk, I will review these puzzles and the efforts to solve them. [Preview Abstract] |
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