7,675 research outputs found

    Spontaneous Lorentz Violation, Nambu-Goldstone Modes, and Massive Modes

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    In any theory with spontaneous symmetry breaking, it is important to account for the massless Nambu-Goldstone and massive Higgs modes. In this short review, the fate of these modes is examined for the case of a bumblebee model, in which Lorentz symmetry is spontaneously broken.Comment: 5 pages. Presented at the Fifth Meeting on CPT and Lorentz Symmetry, Bloomington, Indiana, June 28-July 2, 201

    QED Tests of Lorentz Symmetry

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    A status report is given of some recent theoretical and experimental investigations looking for signals of Lorentz violation in QED. Experiments with light, charged particles, and atoms have exceptional sensitivity to small shifts in energy caused by Lorentz violation, including effects that could originate from new physics at the Planck scale.Comment: Talk presented at the Third Meeting on CPT and Lorentz Symmetry, Bloomington, IN, August, 2004; 9 page

    Nambu-Goldstone and Massive Modes in Gravitational Theories with Spontaneous Lorentz Breaking

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    Spontaneous breaking of local Lorentz symmetry is of interest as a possible mechanism originating from physics at the Planck scale. If such breaking occurs, however, it raises the questions of what the fate of the Nambu-Goldstone modes is, whether a Higgs mechanism can occur, and whether additional massive modes (analogous to the Higgs particle) can appear. A summary of some recent work looking at these questions is presented here.Comment: Talk presented at the Fourth Meeting on CPT and Lorentz Symmetry, Bloomington, IN, August, 2007; 7 pages. Typos correcte

    Wave-Packet Revivals for Quantum Systems with Nondegenerate Energies

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    The revival structure of wave packets is examined for quantum systems having energies that depend on two nondegenerate quantum numbers. For such systems, the evolution of the wave packet is controlled by two classical periods and three revival times. These wave packets exhibit quantum beats in the initial motion as well as new types of long-term revivals. The issue of whether fractional revivals can form is addressed. We present an analytical proof showing that at certain times equal to rational fractions of the revival times the wave packet can reform as a sum of subsidiary waves and that both conventional and new types of fractional revivals can occur.Comment: accepted for publication in Physics Letters

    Industrial application experiment series

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    Two procurements within the Industrial Application Experiment Series of the Thermal Power Systems Project are discussed. The first procurement, initiated in April 1980, resulted in an award to the Applied Concepts Corporation for the Capital Concrete Experiment: two Fresnel concentrating collectors will be evaluated in single-unit installations at the Jet Propulsion Laboratory Parabolic Dish Test Site and at Capitol Concrete Products, Topeka, Kansas. The second procurement, initiated in March 1981, is titled, "Thermal System Engineering Experiment B." The objective of the procurement is the rapid deployment of developed parabolic dish collectors
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