Bulletin of the American Physical Society
2010 Annual Meeting of the California-Nevada Section of the APS
Volume 55, Number 12
Friday–Saturday, October 29–30, 2010; Pasadena, California
Session D2: Gravitation and Astrophysics II |
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Chair: Michelle Poliskie, Solyndra Room: Building 33 - East Bridge Physics Lecture Hall, Room 201 |
Friday, October 29, 2010 4:00PM - 4:12PM |
D2.00001: New Identifications of Sulfur in the Chandra Spectrum of Procyon Jaan Lepson, Maria Obst, Peter Beiersdorfer We report here on new identifications of sulfur in the extreme ultraviolet spectrum of Procyon, combining laboratory measurements, new theoretical calculations, and new observations with the Chandra Low Energy Transmission Grating Spectrometer. We measured intermediate charge states of sulfur (S V - S XII) in the EUV region, 20 - 75 {\AA}, using the Lawrence Livermore National Laboratory's electron beam ion trap EBIT-II, which has been optimized for laboratory astrophysics studies. This allowed us to measure numerous lines previously unidentified in existing atomic databases [1]. We combined these measurements with new calculations using the Flexible Atomic Code [2] to create a hybrid spectrum using measured line wavelengths combined with line intensities calculated for the density of Procyon's corona. We then used this hybrid spectrum to identify sulfur in a Chandra spectrum of Procyon utilizing new observations that doubled the amount of observing time for this target. We found new identifications of sulfur that accounts for many of the previously unassigned lines in the EUV region.\\[4pt] [1] J. K. Lepson et al. ApJ, 625, 1045 (2005).\\[0pt] [2] M. F. Gu, Can J. Phys, 86, 675 (2008). [Preview Abstract] |
Friday, October 29, 2010 4:12PM - 4:24PM |
D2.00002: Insights and possible resolution to the information loss paradox via the tunneling picture Douglas Singleton, Elias Vagenas, Tao Zhu, Ji-Rong Ren This paper investigates the information loss paradox in the WKB/tunneling picture of Hawking radiation. In the tunneling picture one can obtain the tunneling amplitude to all orders in $\hbar$. However all terms beyond the lowest, semi-classical term involve unknown constants. Despite this we find that one can still arrive at interesting restrictions on Hawking radiation to all orders in $\hbar$: (i) Taking into account only quantum corrections the spectrum remains thermal to all orders. Thus quantum corrections by themselves will not resolve the information loss paradox. (ii) The quantum corrections do imply that the temperature of the radiation goes to zero as the mass of the black hole goes to zero. This is in contrast to the lowest order result where the radiation temperature diverges as the mass of the black hole goes to zero. (iii) Finally we show that by taking both quantum corrections and back reaction into account it is possible under specific conditions to solve the information paradox by having the black hole evaporate completely with the information carried away by the correlations of the outgoing radiation. [Preview Abstract] |
Friday, October 29, 2010 4:24PM - 4:36PM |
D2.00003: Scientific Visualization of Extra Dimensions Don V. Black In the 21st Century, many theoretical physicists claim that higher dimensions may indeed exist. Arkani-Hamed, Dimopoulos, \& Dvali (ADD) and Randall-Sundrum (RS), in addition to Kaluza-Klein (KK) and M-string theorists, have introduced reasonable explanations for the existence of heretofore ``invisible'' higher dimensions. Whether or not these extra dimensions actually exist is irrelevant to their contributions to the visionary conceptualization associated with novel and improved mathematical and physical analysis. Envisioning extra dimensions beyond the three of common experience is a daunting challenge for three dimensional observers. Intuition relies on experience gained in a three dimensional environment. Gaining experience with virtual four dimensional objects and virtual three manifolds in four-space on a personal computer may provide the basis for an intuitive grasp of four dimensions. This presentation is a video ``outtake'' of the author's research into ``Visualizing Extra Spatial Dimensions'' at the University of California at Irvine. [Preview Abstract] |
Friday, October 29, 2010 4:36PM - 4:48PM |
D2.00004: The Big Bang and Inflation United by an Analytic Solution Shih-Hung Chen, Itzhak Bars Inflation can solve many cosmological problems such as the horizon and the flatness problem. It also provides a natural mechanism of generating primordial perturbation. Introducing homogeneous scalar field ``inflaton(s)'' is a common way of generating inflation, however, even the dynamics of the simplest inflation model (single inflaton, canonically normalized, minimally coupled to gravity) is difficult to solve. This is because the equations of motion are second order coupled nonlinear differential equations. These equations are usually approached by approximation or numerical method. In this talk I will introduce an inflation model inspired by 2T-Physics where the dynamics of the background evolution can be solved analytically. This solution provides a natural starting point of the universe and provides a specific time after the Big Bang when inflation starts. The analytic background solution also helps us solving the perturbation equation (Mukhanov equation) more accurately. The proposed model although interesting but is still lacking a mechanism of stopping the inflation. The future directions of improving this model will be pointed out at the end of this talk. [Preview Abstract] |
Friday, October 29, 2010 4:48PM - 5:00PM |
D2.00005: On Some Theoretical Models of Dark Energy and Relations between Them Ratbay Myrzakulov There are exist two types of theoretical models of dark energy (DE). First type models are given by General Relativity (GR) that is by Einstein equations with some sources (usual scalar fields, phantom fields, k-essence and so on). Second type models are given by some modified gravity theories like F(R), F (G), F(T) etc and consider DE as geometrical properties of spacetime without any matter sources. In this talk we consider some theoretical models of DE. Also we study the relations between these models. In particular, we show that modified teleparallel gravity or F(T) gravity and k-essence is equivalent each to other. Finally we present some new classes theoretical models of DE. [Preview Abstract] |
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