Bulletin of the American Physical Society
2012 Annual Meeting of the California-Nevada Section of the APS
Volume 57, Number 13
Friday–Saturday, November 2–3, 2012; San Luis Obispo, California
Session D1: Gravitation and Quantum Mechanics |
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Chair: Andreas Bill, California State University, Long Beach Room: Business 003 0205 |
Friday, November 2, 2012 4:12PM - 4:24PM |
D1.00001: Rapid Bayesian Triangulation of Gravitational Wave Inspirals for Advanced LIGO Leo Singer, Larry Price Potential electromagnetic counterparts of compact binary mergers detectable by ground-based gravitational wave detectors fade rapidly. In the last joint LIGO--Virgo science run, a coincidence-based triangulation code produced sky maps for rapid telescope pointing. We are improving upon it with a more accurate Bayesian sky localization algorithm that takes as input the matched-filter amplitude and time-of-arrival. We review the parameter estimation accuracy of matched filters, comparing the often-used Cram\'{e}r-Rao bound with the tighter, but less well known, Barankin bound. We then describe our new sky localization algorithm and its performance. [Preview Abstract] |
Friday, November 2, 2012 4:24PM - 4:36PM |
D1.00002: Comparing Numerical Relativity and Black Hole Perturbation Waveforms for Intermediate Mass Ratio Black Hole Binaries Derek Nelson, Steve Drasco Advanced gravitational-wave observatories with broadened frequency windows will soon be online. Intermediate Mass Ratio Inspirals are source candidates in the newly exposed low frequencies. These are a class of compact binary coalescences containing stellar-mass compact objects and black holes with masses on the order of hundreds to perhaps thousands of solar masses. Waves from these systems must be accurately and efficiently modeled in order to enable observations. A possible substitute for the current waveform model that assumes slow motion are waveforms calculated with a perturbative technique based on the mass ratio, a more stable small parameter. We implement an inexpensive version of this model and compare the corresponding waveforms with impractically expensive waveforms from full Numerical Relativity simulations. I discuss the somewhat surprising success of the comparisons for systems with simple motion and nearly equal-mass binaries. I will also discuss similar comparisons currently underway for more complex motion and mass distributions. [Preview Abstract] |
Friday, November 2, 2012 4:36PM - 4:48PM |
D1.00003: Aspects of General Relativity in 1+1 Dimensions Richard Mellinger, Scott Fraser, Thomas Gutierrez What would be the properties of a universe with only one spatial dimension and one time dimension? General relativity in 1+1 dimensions is unique since the two curvature terms in the Einstein field equations cancel. This makes the Einstein field equations algebraic rather than differential equations. This special feature can make 1+1 dimensionality attractive as an instructional tool to simplify the mathematics that many beginners find opaque. We explore the implications and features of the Einstein field equations in 1+1 dimensions and find they provide a surprisingly rich and interesting model. [Preview Abstract] |
Friday, November 2, 2012 4:48PM - 5:00PM |
D1.00004: Binding of Small Black Holes to a Brane in Asymptotically Randall-Sundrum Spacetimes Scott Fraser, Douglas Eardley General relativity in five spacetime dimensions can be used to model our universe as a surface (brane) in an extra-dimensional bulk space. We study the binding of small black holes to a brane with positive brane tension and a mirror (orbifold) symmetry, in asymptotically Randall-Sundrum spacetimes. We find that a small black hole that is on the brane has a substantial gravitational binding energy, hence it is stable against escaping from the brane into the bulk. We also find that a new kind of static black hole can exist at a certain location in the bulk; this new black hole is unstable to falling either towards or away from the brane. These results are obtained from a variational principle based on a version of the first law of black hole mechanics. [Preview Abstract] |
Friday, November 2, 2012 5:00PM - 5:12PM |
D1.00005: Precision Optical Systems for Short-range Tests of Gravity Holly Leopardi, C.D. Hoyle, David Smith Due to the incompatibility of the Standard Model and General Relativity (GR), tests of gravity remain at the forefront of experimental physics. At Humboldt State University, undergraduates and faculty are developing an experiment that will test gravitational interactions below the 50-micron distance scale. The experiment will measure the twist of a torsion pendulum as an attractor mass is oscillated nearby in a parallel-plate configuration, providing a time varying torque on the pendulum. The size and distance dependence of the torque variation will provide means to determine deviations from accepted models of gravity on untested distance scales. To observe the twist of the pendulum inside the vacuum chamber, an optical system with nano-radian precision is required. This talk will focus on the improvements made to the optical system such that it is expected to achieve the required sensitivity, as well as recent data taken with the updated optical system. A future improved optical system under development that will implement a small-angle interferometer to measure the twist of the pendulum will also be presented. [Preview Abstract] |
Friday, November 2, 2012 5:12PM - 5:24PM |
D1.00006: Tests of Gravity Below the 50-micron Distance Scale David Smith, C.D. Hoyle, Holly Leopardi Though it is the oldest recognized of the fundamental forces, tests of gravity remain at the forefront of experimental physics research. Due to the incompatibility of the Standard Model and General Relativity, there is no accepted Unified Field Theory, though some attempts to construct such a model via String Theory predict more than three spatial dimensions that could alter the gravitational Inverse-Square Law at short distances. Certain scenarios also predict unobserved subatomic particles that may cause short-range violations of the Weak Equivalence Principle. The Gravitational Research Laboratory at Humboldt State University, a collaboration of undergraduate students and faculty, is developing an experiment that will test gravitational interactions below the 50-micron distance scale. The experiment will measure the torque applied to a torsion pendulum as an attractor mass is oscillated nearby. The size and distance dependence of the torque variation will provide a means to determine any deviations from Newtonian gravity at heretofore untested scales. The major components of the experiment have been designed and fabricated including a novel stepped parallel-plate torsion pendulum and a high-precision optical angle detection system. This talk will provide a general overview of the experiment and focus primarily on current status and expected outcomes. [Preview Abstract] |
Friday, November 2, 2012 5:24PM - 5:36PM |
D1.00007: Foucault's Pendulum, Analog for an Electron Spin State Rebecca Linck The classical Lagrangian that describes the coupled oscillations of Foucault's pendulum presents an interesting analog to an electron's spin state in an external magnetic field. With a simple modification, this classical Lagrangian yields equations of motion that directly map onto the Schrodinger-Pauli Equation. This analog goes well beyond the geometric phase, reproducing a broad range of behavior from Zeeman-like frequency splitting to precession of the spin state. By demonstrating that unmeasured spin states can be fully described in classical terms, this research opens the door to using the tools of classical physics to examine an inherently quantum phenomenon. [Preview Abstract] |
Friday, November 2, 2012 5:36PM - 5:48PM |
D1.00008: A Metric on the Space of Quantum Fields Michael Maroun Over the past 60 years, there have been many attempts at giving a precise mathematical definition of a quantum field. A space of quantum fields is proposed as the space of operator-valued generalized functions and arguments are given justifying the need for such general objects. A metric is then constructed on this space in such a way that it is dynamically defined through the Hamiltonian. This then allows one to keep track of differences between ideal states in interacting theories by comparing them to the corresponding ideal states in asymptotically free theories. For simplicity, an emphasis is placed on scalar $\varphi^4$ theory. The metric then allows one to construct geometric and topological attributes in order to find differences that characterize changes between asymptotically free theories to that of interacting ones. [Preview Abstract] |
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