Bulletin of the American Physical Society
2009 APS April Meeting
Volume 54, Number 4
Saturday–Tuesday, May 2–5, 2009; Denver, Colorado
Session T8: Gravitation and Cosmology 
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Sponsoring Units: DAP Chair: Deirdre Shoemaker, Georgia Institute of Technology Room: Governor's Square 17 
Monday, May 4, 2009 3:30PM  3:42PM 
T8.00001: On Origin of NonGaussianity Outside the Horizon from Preheating after Inflation Yuki Watanabe, Eiichiro Komatsu We show that preheating after inflation produces nonGaussianity of primordial curvature perturbations on large scales. It can be shown that entropy perturbations imprinted on a large scale can generate adiabatic perturbations on the same scale. Those generated adiabatic modes are nonGaussian due to mode couplings if nonlinearity is important. The previous work on nonGaussianity from preheating used the $\delta N$ formalism, coupled with the lattice simulation; however, the validity of $\delta N$ formalism has not been verified for preheating. While we also use the lattice simulation, we have studied this issue using a different approach, namely, a covariant formalism for nonlinear perturbations of cosmological scalar fields. [Preview Abstract] 
Monday, May 4, 2009 3:42PM  3:54PM 
T8.00002: Cosmological constraints on general, single field inflation Nishant Agarwal, Rachel Bean Inflation is now an accepted paradigm in standard cosmology. It lacks, however, a firm physical theory, with many possible theoretical origins beyond the simplest, canonical, slowroll inflation, including DiracBornInfeld inflation and kinflation. We discuss how a hierarchy of Hubble flow parameters, extended to include the evolution of the inflationary sound speed, can be applied to compare a general, single field inflationary action with cosmological observational data. By integrating the full flow and perturbation equations to obtain precise scalar and tensor primordial power spectra, we use a MonteCarloMarkovChain approach to constrain the properties of general, single field inflation by comparing with recent cosmic microwave background and largescale structure observations. [Preview Abstract] 
Monday, May 4, 2009 3:54PM  4:06PM 
T8.00003: F(R) Chameleon Models Require Fine Tuning Andrew Lundgren, Eanna Flanagan Can the accelerating expansion of the universe be explained by modifying Einstein's theory? Explanations in term of the cosmological constant or some other type of dark energy tend to require very unnatural energy scales. We consider instead a modification of the equations of motion of general relativity called F(R) gravity. The Ricci scalar in the gravitational action is replaced with a function of the Ricci scalar. It is typically very difficult to modify general relativity without ruining its successes. A class of F(R) models called chameleon theories can preserve these successes while also explaining the cosmic acceleration. We show that the constraints placed by tests of gravitation require that the chameleon theories include finetuned parameters. These fine tunings do not rule out models of this type, but they do make them less attractive as an alternative explanation to dark energy. [Preview Abstract] 
Monday, May 4, 2009 4:06PM  4:18PM 
T8.00004: Parameter Estimation Forecasts in Cosmology Rahul Biswas In the current era of precision cosmology, new extremely well planned missions are being designed to study cosmology to unprecedented detail. This will not only allow us to constrain the free parameters in the standard model of cosmology, but also to test the departures (or lack of departure) from the model itself. In order to optimize the scientific impact of these missions, it is therefore essential to forecast the constraints accurately, as well as study different ways in which the data may used to to constrain cosmology. We discuss forecasts, in particular pertaining to dark energy studies, from planned observational surveys. [Preview Abstract] 

T8.00005: ABSTRACT WITHDRAWN 
Monday, May 4, 2009 4:30PM  4:42PM 
T8.00006: Acceleration and horizon problem within interactive Bose gas model of dark energy German Izquierdo, Besprosvany Jaime We study the dynamics of a FRW universe containing a selfinteracting BoseEinstein gas. The interaction between the particles of the gas gives accelerated solutions. We demonstrate how this model can be applied to describe the early stage of accelerated expansion, solving the horizon problem and respecting the nucleosynthesis scenario. We also demostrate under which conditions the model can describe the present acceleated expansion. [Preview Abstract] 
Monday, May 4, 2009 4:42PM  4:54PM 
T8.00007: Dark Energy and Dark Matter: two faces of the same problem? Mihai Bondarescu, Jayashree Balakrishna, Ruxandra Bondarescu We discuss the possibility that a family of very light scalar particles is behind both Dark Matter and Dark Energy. When the mass is chosen appropriately, agglomerations of such particles would naturally exhibit no smallscale structure and would be supported against gravitational collapse by the Heisenberg uncertainty principle alone, very much like the previously studied Boson Stars. In the early Universe, when the cosmological horizon was smaller then the characteristic size of one of these particles, the presence of such a scalar field would accelerate inflation in a manner similar to the way Dark Energy accelerates the expansion of the universe today. At least two particles of different masses would be necessary to explain the effects attributed to both dark energy and dark matter. If such a particle were to exist, the existence of a second similar object is more likely. This work is in progress. [Preview Abstract] 
Monday, May 4, 2009 4:54PM  5:06PM 
T8.00008: Big Bang Fuel Discovered and Demonstrated Charles Sven I will provide the four major components, with demonstration and documentation, necessary to understand how our universe arrived at its current state. These four components are: 1st A scenario explaining the Big Bang. 2nd. A scenario explaining the distribution of all celestial objects. 3rd A scenario explaining Earth's location in our universe. 4th Observations supporting all the above, from NASA, Stanford Labs, and other equivalent sources. [Preview Abstract] 
Monday, May 4, 2009 5:06PM  5:18PM 
T8.00009: Cosmological quantum Partition Paul Suh One of the unexplained conundrums of modern science is the existence of the dark matter and energy that do not quantum interact with the ordinary matter and energy, while equally interacting gravitationally. The manifestation of this ``quantum partition'' is simulated by introducing a quantum potential barrier between the two universes of matter and energy. This simulation is shown to be equivalent to the ``dualtime physics'' that leads to the concept of ``tangential freedom,'' which indicates the literal existence of the quantum partition between the two universes. Here matter and energy autonomously turn around and reflect back into their own universe like boomerangs (rather than like the rebounding ball from a potential barrier wall). Thus, dark matter and energy do not quantum interact with ordinary matter and energy! The physics of dark matter and energy is developed in a manner commensurate with the known physics of ordinary matter and energy. With this development, in the formative approximations, practically all the physical and cosmological puzzles (which are unexplained by the standard theories in vogue) are explainable. (The paper is available from pksuh@msn.com). [Preview Abstract] 
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