854 research outputs found
Vector Superfields and Lorentz Violation
We extend Lorentz-violating Supersymmetry models to include vector
superfields. The CPT-preserving model generalizes easily, while the obvious
attempt at generalizing the CPT-violating model meets serious obstructions.
Generalizations of the CPT-preserving but Lorentz-Violating model to higher
dimensions are also straightforward. Compactification is used to reduce the
six-dimensional theory to an Lorentz-violating theory in four
dimensions, while the ten-dimensional theory is used to produce an
Lorentz-violating theory. This may be useful in future
constructions involving Ads/CFT correspondence with Lorentz violation.Comment: 5 pages, submitted to Physical Review
Nonrelativisitic Ideal Gasses and Lorentz Violations
We develop statistical mechanics for a nonrelativisitic ideal gas in the
presence of Lorentz violating background fields. The analysis is performed
using the Standard-Model Extension (SME). We derive the corresponding laws of
thermodynamics and find that, to lowest order in Lorentz violation, the scalar
thermodynamic variables are corrected by a rotationally invariant combination
of the Lorentz terms which can be interpreted in terms of a (frame dependent)
effective mass. We find that spin couplings can induce a temperature
independent polarization in the gas that is not present in the conventional
case.Comment: 6 pages, proceedings for CPT and Lorentz Symmetry, Bloomington, IN,
200
Deformed Instantons
In this talk, instantons are discussed in the presence of Lorentz violation.
Conventional topological arguments are applied to classify the modified
solutions to the Yang-Mills equations according to the topological charge.
Explicit perturbations to the instantons are calculated in detail for the case
of unit topological charge.Comment: 6 pages, proceedings for CPT and Lorentz Symmetry, Bloomington, IN,
200
Lorentz Violation and Extended Supersymmetry
We construct a collection of Lorentz violating Yang-Mills theories exhibiting
supersymmetry.Comment: Presented at the Fifth Meeting on CPT and Lorentz Symmetry,
Bloomington, Indiana, June 28-July 2, 201
Cherenkov radiation with massive, CPT-violating photons
The source of CPT violation in the photon sector of the Standard Model Extension arises from a Chern-Simons-like contribution that involves a coupling to a fixed background vector field k(AF)(mu). These Lorentz- and CPT-violating photons have well-known theoretical issues that arise from missing states at low momenta when k(AF)(mu) is timelike. In order to make the theory consistent, a tiny mass for the photon can be introduced, well below current experimental bounds. The implementation of canonical quantization can then be implemented as in the CPT-preserving case by using the Stuckelberg mechanism. We explicitly construct a covariant basis of properly normalized polarization vectors at fixed three-momentum satisfying the momentum space field equations, in terms of which the vector field can be expanded. As an application of the theory, we calculate the Cherenkov radiation rate for the case of purely timelike k(AF)(mu) and find a radiation rate at high energies that has a contribution that does not depend on the mass used to regulate the photons
Quaternionic Formulation of the Dirac Equation
The Dirac equation with Lorentz violation involves additional coefficients
and yields a fourth-order polynomial that must be solved to yield the
dispersion relation. The conventional method of taking the determinant of
matrices of complex numbers often yields unwieldy dispersion
relations. By using quaternions, the Dirac equation may be reduced to form in which the structure of the dispersion relations become more
transparent. In particular, it is found that there are two subsets of
Lorentz-violating parameter sets for which the dispersion relation is easily
solvable. Each subset contains half of the parameter space so that all
parameters are included.Comment: Presented at the Fifth Meeting on CPT and Lorentz Symmetry,
Bloomington, Indiana, June 28-July 2, 201
Gupta-Bleuler Photon Quantization in the SME
Photon quantization is implemented in the standard model extension (SME)
using the Gupta-Bleuler method and BRST concepts. The quantization prescription
applies to both the birefringent and non-birefringent CPT-even couplings. A
curious incompatibility is found between the presence of the Lorentz-violating
terms and the existence of a nontrivial conjugate momentum yielding
problems with covariant quantization procedure. Introduction of a mass
regulator term can avoid the vanishing of and allows for the
implementation of a covariant quantization procedure. Field-theoretic
calculations involving the SME photons can then be performed using the mass
regulator, similar to the conventional procedure used in electrodynamics for
infrared-divergence regulation.Comment: 13 page
Bose-Einstein Condensates as a Probe for Lorentz Violation
The effects of small Lorentz-violating terms on Bose-Einstein condensates are
analyzed. We find that there are changes to the phase and shape of the
ground-state wave function that vary with the orientation of the trap. In
addition, spin-couplings can act as a source for spontaneous symmetry breaking
in ferromagnetic condensates making them sensitive probes for fundamental
symmetry violation
- …