Bulletin of the American Physical Society
2010 Fall Meeting of the APS Division of Nuclear Physics
Volume 55, Number 14
Tuesday–Saturday, November 2–6, 2010; Santa Fe, New Mexico
Session NH: Nuclear Theory: QED-QCD |
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Chair: Joaquin Drut, Ohio State University Room: Lamy |
Saturday, November 6, 2010 10:30AM - 10:42AM |
NH.00001: QED in strong external fields Heli Honkanen, Pieter Maris, James Vary, Stan Brodsky Recent interest in strong field QED at RHIC has brought new emphasis on the need for robust methods for solving physical systems with two or more distinct scales. We employ Hamiltonian light-front quantum field theory in a basis function approach to solve the non-perturbative problem of an electron in a strong scalar transverse confining potential - an example that is useful for testing other approaches to field theory at strong coupling. We evaluate both the invariant mass spectra and the anomalous magnetic moment of the lowest state to provide results for this complicated two-scale system. The weak external field limit of the anomalous magnetic moment agrees with the result of QED perturbation theory within the anticipated accuracy. [Preview Abstract] |
Saturday, November 6, 2010 10:42AM - 10:54AM |
NH.00002: On the nonperturbative calculation of wave functions in quantum field theories John Hiller The understanding of hadronic physics would benefit greatly from a method to compute hadronic wave functions nonperturbatively in quantum chromodynamics. Work on the development of such a method, in the context of quantum electrodynamics, will be discussed. The method is based on a light-front Hamiltonian approach and Fock-state expansions for eigenstates of the Hamiltonian. Wave functions enter explicitly in this expansion and can be used to calculate properties of the eigenstate. The construction and solution of bound-state eigenvalue problems will be outlined. [Preview Abstract] |
Saturday, November 6, 2010 10:54AM - 11:06AM |
NH.00003: Application of a nonperturbative light-front Hamiltonian method to the solution of a gauge theory Sofia Chabysheva As a step toward the development of a nonperturbative method for the solution of quantum chromodynamics, we consider the solution of quantum electrodynamics with a light-front Hamiltonian approach. Details and results of recent calculations will be given, to illustrate the applicability to a gauge theory. As a benchmark, we consider the anomalous moment of the electron in a Fock basis that includes up to two virtual photons. [Preview Abstract] |
Saturday, November 6, 2010 11:06AM - 11:18AM |
NH.00004: Heavy Quark States with Relativistic Confinement Richard Silbar, Terrence Goldman Constituent quark models of hadronic states are usually studied non-relativistically, although with various sophistications such as relativized kinetic energy, highly structured interaction potentials including harmonic confinement, and recently, components motivated by field theory [1]. Confinement is a critical element, but it is a linear confining potential that is found by lattice work in fully relativistic, field theory using Dirac bispinors. Recalling an early observation [2] that non-relativistic reduction of a linear potential approach produces an effective harmonic confining potential, we have reconsidered relativistic modeling with a view towards simplifying the potentials and interactions assumed. We report on progress, in the heavy quark sector, in determining the structure and nature of the potentials required to match the experimentally determined ground states, as well as the radial and orbital excitation spectra. \\[4pt] [1] Di Qing, Xiang-Song Chen and Fan Wang, Phys. Rev. D 58, 114032 (1998).\\[0pt] [2] T. Goldman and S. Yankielowicz, Phys. Rev. D 12, 2910 (1975). [Preview Abstract] |
Saturday, November 6, 2010 11:18AM - 11:30AM |
NH.00005: Toward large-scale many-fermion calculations on Graphics Processing Units Kyle Wendt, Joaquin Drut, Timo Lahde We apply Graphics Processing Units (GPUs) to simulations of quantum many-body systems. Specifically, we study the performance of sparse matrix-vector multiplication and preconditioned conjugate gradient iteration on the NVIDIA Tesla c1060 GPU card. These operations are of direct relevance to Hybrid Monte Carlo calculations at finite temperature and density. We report a CPU-GPU performance comparison for the Fermi Hubbard model in $d+1$ space-time dimensions, where we find speedup factors in excess of $40$. We present an overview of our algorithm, possible optimization strategies and projected performance on the recently released NVIDIA Fermi architecture. [Preview Abstract] |
Saturday, November 6, 2010 11:30AM - 11:42AM |
NH.00006: Behaviors of Early Time Gluon Fields in High Energy Nuclear Collisions Guangyao Chen, Rainer Fries We discuss the properties of the early time gluon fields in ultra-relativistic heavy ion collisions in a quasi-classical approximation. Using recursive solutions of the Yang-Mills equations for two intersecting color currents on the light cone, we describe the classical gluon field and its energy momentum tensor at small proper times $\tau$ after the collision of two nuclei. We explicitly check energy momentum conservation up to forth order. We compute multi-gluon correlation functions in the McLerran-Venugopalan model which are necessary to calculate the expectation value of the energy momentum tensor. An interpolation with linear gluon fields at large times provides a good approximation of the full time evolution. Our results can also be used to create an event-by- event sample of early time gluon fields. [Preview Abstract] |
Saturday, November 6, 2010 11:42AM - 11:54AM |
NH.00007: The relativistic time-dependent Aharonov-Bohm effect and the topology of the electromagnetic vacuum Athanasios Petridis, Zachary Kertzman The Aharonov-Bohm (A-B) effect reveals some topological properties of the vacuum. In particular, it is connected to the fundamental homotopy group of the gauge group. For the effect to exist, the latter must be non-trivial. Therefore, in the case of electromagnetic interactions the experimental verification of the A-B effect can be a test of the vacuum topology of the Standard Model since, in this model, the electromagnetic-sector gauge group is irregularly embedded in the electroweak one. The magnetic, relativistic time-dependent A-B effect is studied by developing numerical solutions to the minimally-coupled Dirac equation. The contributions of a magnetic potential associated with an infinitely-long solenoid and of possible, residual, dipole fields are evaluated. It is shown that time-dependent interferometry signals exhibit a characteristic non-monotonic behavior as functions of the field strength allowing for a clear isolation of the A-B effect. [Preview Abstract] |
Saturday, November 6, 2010 11:54AM - 12:06PM |
NH.00008: Quarkeosynthesis: a correct science of nuclear structure, forces and energy William Webb Quarkeosynthesis owes its success to the simple postulation that during synthesis of nuclei it's the Quarks that do the combining: not whole nucleons. String-like quarks combine to build more massive rope-like Quarks: hence the title Quarkeosynthesis. Nuclei are thus all made of three loops of flexible string-like material that rotate with a circular ring shape. All nuclei have two positive charged Quarks and a single negative charged Quark. Electrostatic attraction and repulsion bind each threesome in its structure. There are no special nuclear strong or weak forces and no gluon material or bosons. Quarks rotate at high speeds so a portion of their mass is relativistic. Intrinsic mass of all small mass nuclei neighbors 72.5\%. Quarks have a radial wave motion. Waves move with the same speed as the rotational speed of the Quark itself so Quarks can obey the Einstein mass-energy equation. Wave energy is an integral part of a nucleus' total mass-energy and determines its binding energy. Quarkeosynthesis correctly determines, without exception, the beta decay and stability of the 65 least massive nuclei. A primer on Quarkeo-synthesis is available from wbwebb@rconnect.com. [Preview Abstract] |
Saturday, November 6, 2010 12:06PM - 12:18PM |
NH.00009: Mass Energy Equivalence Formula Must Include Rotational and Vibrational Kinetuic Energies as Well As Potential Energies Stewart Brekke Originally Einstein proposed the the mass-energy equivalence at low speeds as $E=mc^2 + 1/2 mv^2$. However, a mass may also be rotating and vibrating as well as moving linearly. Although small, these kinetic energies must be included in formulating a true mathematical statement of the mass-energy equivalence. Also, gravitational, electromagneic and magnetic potential energies must be included in the mass-energy equivalence mathematical statement. While the kinetic energy factors may differ in each physical situation such as types of vibrations and rotations, the basic equation for the mass- energy equivalence is therefore $E = m_0c^2 + 1/2m_0v^2 + 1/2I\omega^2 + 1/2kx^2 + W_G + W_E + W_M$. [Preview Abstract] |
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