Bulletin of the American Physical Society
APS April Meeting 2012
Volume 57, Number 3
Saturday–Tuesday, March 31–April 3 2012; Atlanta, Georgia
Session D7: Inflation and Cosmology |
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Sponsoring Units: DAP Chair: Stephon Alexander, Haverford College Room: Embassy D |
Saturday, March 31, 2012 3:30PM - 3:42PM |
D7.00001: Inertial Systems Kinematically Defined in an Inflationary Universe David Savickas The cosmological background radiation is observed to be isotropic only within a coordinate system that is at rest relative to its local Hubble drift. This indicates that the Hubble motion describes the recessional motion of an inertial system that is at rest relative to its local Hubble drift. It is shown that when the Hubble parameter is kinematically defined directly in terms of the positions and velocities of mass particles in the universe, it then also defines inertial systems themselves in terms of the distribution and motion of mass particles. It is independent of the velocity of photons because photons always have a speed $c$ relative to the inertial system in which they are located and therefore the definition of their velocity depends on the definition of the Hubble parameter itself and cannot be used to define $H$. The time derivative of the kinematically defined Hubble parameter is always positive and repulsive. It is shown to oppose the negative attractive acceleration of gravitation in a manner that leads to a universe that is balanced at the time of its origin so that $H$ approaches zero as the universe expands to infinity. [Preview Abstract] |
Saturday, March 31, 2012 3:42PM - 3:54PM |
D7.00002: Numerical Simulation of Chern-Simons Inflation David Garrison, Annie Preston, Stephon Alexander In this talk we show numerical results of the Chern-Simons Inflation Model proposed by Alexander, Marciano and Spergel. In this model, the Chern-Simons interaction of vector fields plays a central role in generating the inflationary epoch. According to the model, Inflation begins with a plasma made of interacting gauge fields and fermions. The Chern-Simons interaction then drives energy from the initial random spectrum into a narrow-band of frequencies at superhorizon scales. The fermion current also amplifies the gauge field at superhorizon scales. These gauge fields when combined with the Friedman equations can be broken into a system of hyperbolic equations and modeled numerically. We show that the amplification of horizon sized gauge fields produces the conditions to cause more than 60 e-folds of inflation. [Preview Abstract] |
Saturday, March 31, 2012 3:54PM - 4:06PM |
D7.00003: Supersymmetric standard model inflation in the Planck era Nobuchika Okada, Masato Arai, Shinsuke Kawai We propose a cosmological inflationary scenario based on the supergravity-embedded Standard Model supplemented by the right-handed neutrinos. We show that with an appropriate K\"{a}hler potential the $L$-$H_u$ direction gives rise to successful inflation that is similar to the recently proposed gravitationally coupled Higgs inflation model but is free from the unitarity problem. The mass scale $M_R$ of the right-handed neutrinos is subject to the seesaw relation and the present 2-$\sigma$ constraint from the WMAP7-BAO-$H_0$ data sets its lower bound $M_R\ga$ 1 TeV. Generation of the baryon asymmetry is naturally implemented in this model. We expect within a few years new observational data from the Planck satellite clearly discriminates this model from other existing inflationary models arising from the same Lagrangian,and possibly yields stringent constraints on $M_R$. [Preview Abstract] |
Saturday, March 31, 2012 4:06PM - 4:18PM |
D7.00004: ABSTRACT WITHDRAWN |
Saturday, March 31, 2012 4:18PM - 4:30PM |
D7.00005: W-band Measurement of Cosmic Microwave Background Polarization with QUIET Makoto Nagai QUIET is a ground-based experiment designed to detect $B$-modes in the CMB polarization induced by primordial gravitational waves created during the inflation era. QUIET employs coherent receivers and assembles them into two large arrays, with 19 modules for the Q band (43 GHz) and with 90 modules for the W band (95 GHz), respectively. The telescope was located on the Chajnantor plateau, Chile at an altitude of 5,080 m. We started the operation since 2008 October to observe CMB in the four fields of the sky. After the operation in Q band, we have collected 5,275 hours of CMB data in W band from 2009 July to 2010 December. W-band data has better spatial resolution and less foreground contamination than Q-band data. In this talk, I will present our status of the W-band analysis with one of our two analysis frameworks, based on pseudo-$C_l$ estimator. The analysis essentially follows the steps of calibration, data selection, and power spectra estimation. We also require to pass suites of null tests and to complete a sophisticated systematics study as validation, before looking at the results: the $EE$, $BB$, and $EB$ powers. We expect that the robust analysis strategy provides us the least systematic errors as well as one of the best results for the $B$-mode measurements. [Preview Abstract] |
Saturday, March 31, 2012 4:30PM - 4:42PM |
D7.00006: The First Billion Years: From the First Stars to the First Galaxies John Wise, Matthew Turk, Michael Norman, Tom Abel, Britton Smith The first stars in the universe are thought to be massive, forming in dark matter halos with masses around 10$^6$ solar masses. Recent simulations suggest that these metal-free (Population III) stars may form in binary or multiple systems. Because of their high stellar masses and small host halos, their feedback ionizes the surrounding 3 kpc and drives the majority of the gas from the potential well. The next generation of stars then must form in this gas-poor environment, creating the first galaxies that produce the majority of ionizing radiation during cosmic reionization. I will review the latest developments in the field of Population III star formation and feedback and its impact on galaxy formation prior to reionization. In particular, I will focus on the numerical simulations that have demonstrated this sequence of events, ultimately leading to cosmic reionization, and their connections with nearby dwarf galaxies. [Preview Abstract] |
Saturday, March 31, 2012 4:42PM - 4:54PM |
D7.00007: The Dark Energy Survey Brenna Flaugher The Dark Energy Survey Collaboration will soon begin a 5000 sq. deg. imaging survey of the southern galactic cap using a new 520 Megapixel CCD camera, the Dark Energy Camera, with 5 filters (g,r,i,z and Y) mounted on the Blanco 4-meter telescope at Cerro-Tololo Inter-American Observatory. The data will be used to place new and tight constraints on the nature of dark energy via the history of the cosmic expansion rate and the growth of large-scale structure, using the four complementary techniques recommended by the Dark Energy Task Force: weak gravitational lensing, galaxy cluster counts, large-scale structure including baryon acoustic oscillations, and Type Ia supernovae. Installation of the new camera and commissioning on the telescope will take place in early-mid 2012 with the expectation that the survey will begin in late 2012. The science projections and prospects will be described. [Preview Abstract] |
Saturday, March 31, 2012 4:54PM - 5:06PM |
D7.00008: Optimization of Type Ia Supernovae Selection, Photometric Typing, and Cosmology Constraints Eda Gjergo, Jefferson Duggan, John Cunningham, Steve Kuhlmann, Rahul Biswas, Eve Kovacs We present results of an optimization study of selection criteria and photometric identification of Type Ia supernovae. The optimization study is the first to include detailed constraints on cosmology, including a time-dependent component of accelerated expansion. The study is performed on a simulated sample of Type Ia and core collapse supernovae from the Dark Energy Survey. In the next decade the number of detected Type Ia supernovae will increase dramatically (Bernstein et al. 2011, Abel et al. 2009), surpassing the resources available for spectroscopic confirmation of each supernova. This has produced an increased interest in the photometric identification of Type Ia supernovae. In order to improve the constraints on the accelerated expansion of the universe, discovered with Type Ia supernovae in the 1990's (Ries et al. 1998, Perlmutter et al. 1999), photometric typing of SN must be very robust. In this study we compare the template-based PSNID algorithm (Sako et al. 2010), with two Type Ia models MLCS2k2 (Riess et al. 2009) and SALT2 (Guy et al. 2007). We allow the pre-selection cuts, based on signal-to-noise ratios, to vary for each model. The optimal model plus pre-selection cuts is determined from the best cosmology constraint. [Preview Abstract] |
Saturday, March 31, 2012 5:06PM - 5:18PM |
D7.00009: Introducing the Pointon: A Heuristic Model for the Holographic Encoding of the Universe from First Principles Ronald de Strulle, Maximilian Rheinhart Contraction of a cyclic (3+1)d universe is described topologically as the collapse of 3-sphere to a ``pointon.'' A spinning universal energy quantum, characterized by an anti-symmetric relativistic angular momentum 6-tensor, $M^{ab}$. Holographic duals over fractal dimensions persist via spin-spin-spin couplings as r$\to $0. A self-referential proper frame preserves continuity and causality, with t'Hooft conditions shown in equivalence classes of pointonic degrees of freedom, quantized temporally as f(n$\pi )^{-1}$ at first principles. A spin operator, $S$, and propagator (generator), $\xi ^{abc}$, with recursive self-referential coefficient, Ae$^{iln(i)}$, and coupling constant, $\acute{\alpha}}$, where A is a complex number. Recursive cycling over O(3) spin symmetry can describe generally covariant operations on a universal wavefunction. Unwinding of successive rotations of pointon's ``effective'' angular momentum characterized as Markovian quanta over Hausdorff fractal topology, ``act-ing'' over temporal units, per 2$\pi $ rotation, and helicity of proper frame governed by the self-backreaction,. ``Effective'' indicating normalization of, $\hbar$, per cost in entropy, k$_{B}$. Paths of least action for pointon's unwinding to spontaneous symmetry-breaking, from discrete non-interacting regime to surface area maximizing tetron (topological tetrahedroid) regime $\to $ rapid expansion. Duals of ``effective'' informational action and angular momentum transform to linear momentum, mass-energy, and quasi- and virtual bound-state of spacetime fabric. [Preview Abstract] |
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