scholarly journals Nonlinear vacuum electrodynamics and spontaneous breaking of Lorentz symmetry

2020 ◽  
Vol 35 (27) ◽  
pp. 2050174
Author(s):  
C. A. Escobar ◽  
R. Potting
Keyword(s):  
Lorentz Invariance ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Lorentz Symmetry ◽  
Spontaneous Breaking ◽  
Effective Hamiltonian ◽  
First Order ◽  
Superluminal Motion ◽  
Field Fluctuations ◽  
Nonlinear Vacuum Electrodynamics

We study spontaneous breaking of Lorentz symmetry in nonlinear vacuum electrodynamics. Using a first-order formulation of the latter proposed by Plebański, we apply a Dirac constraint analysis and derive an effective Hamiltonian. We show that there exists a large class of potentials for which the effective Hamiltonian is bounded from below, while at the same time possessing local minima in which the field strength acquires a nonzero vacuum expectation value, thereby breaking Lorentz invariance spontaneously. These possible vacua can be classified in four classes, depending on the way Lorentz symmetry is broken. We show that the small field fluctuations around these vacua involve modes for which the dynamics can develop degeneracies, resulting in shock-wave-like and/or superluminal motion. Finally, we study the physical applicability of these models, and show how the Lorentz breaking vacua might in principle be detected by coupling the model to a suitable external current, or to gravity.

scholarly journals SPONTANEOUS VIOLATION OF LORENTZ INVARIANCE AND ULTRA-HIGH ENERGY COSMIC RAYS

2003 ◽  
Vol 12 (07) ◽  
pp. 1279-1287 ◽  
Author(s):  
J. W. MOFFAT
Keyword(s):  
Cosmic Rays ◽  
Lorentz Invariance ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
High Energy ◽  
Spontaneous Breaking ◽  
Ultra High Energy ◽  
High Energy Cosmic Rays ◽  
High Energies ◽  
Local Lorentz Invariance

We propose that local Lorentz invariance is spontaneously violated at high energies, due to a nonvanishing vacuum expectation value of a vector field ϕμ, as a possible explanation of the observation of ultra-high energy cosmic rays with an energy above the GZK cutoff. Certain consequences of spontaneous breaking of Lorentz invariance in cosmology are discussed.

scholarly journals Electroweak Phase Transitions in Einstein’s Static Universe

2018 ◽  
Vol 2018 ◽  
pp. 1-5
Author(s):  
M. Gogberashvili
Keyword(s):  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Electroweak Phase Transition ◽  
Static Universe ◽  
Expectation Value ◽  
First Order ◽  
Higgs Vacuum ◽  
The Standard Model ◽  
Effective Reduction ◽  
New Phase

We suggest using Einstein’s static universe metric for the metastable state after reheating, instead of the Friedman-Robertson-Walker spacetime. In this case, strong static gravitational potential leads to the effective reduction of the Higgs vacuum expectation value, which is found to be compatible with the Standard Model first-order electroweak phase transition conditions. Gravity could also increase the CP-violating effects for particles that cross the new phase bubble walls and thus is able to lead to the successful electroweak baryogenesis scenario.

scholarly journals (j, 0) ⊕ (0, j) COVARIANT SPINORS AND CAUSAL PROPAGATORS BASED ON WEINBERG FORMALISM

1993 ◽  
Vol 02 (02) ◽  
pp. 397-422 ◽  
Author(s):  
D.V. AHLUWALIA ◽  
D.J. ERNST
Keyword(s):  
Perturbation Theory ◽  
Wave Equations ◽  
Lorentz Invariance ◽  
Free Particle ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Arbitrary Spin ◽  
Definition Of ◽  
The Individual ◽  
Particle Propagator

A pragmatic approach to constructing a covariant phenomenology of the interactions of composite high-spin hadrons is proposed. Because there are no known wave equations without significant problems, we propose to construct the phenomenology without explicit reference to a wave equation. This is done by constructing the individual pieces of a perturbation theory and then utilizing the perturbation theory as the definition of the phenomenology. The covariant spinors for a particle of spin j are constructed directly from Lorentz invariance and the basic precepts of quantum mechanics following the logic put forth originally by Wigner and developed by Weinberg. Explicit expressions for the spinors are derived for j=1, 3/2 and 2. Field operators are constructed from the spinors and the free-particle propagator is derived from the vacuum expectation value of the time-order product of the field operators. A few simple examples of model interactions are given. This provides all the necessary ingredients to treat at a phenomenological level and in a covariant manner particles of arbitrary spin.

scholarly journals The Super-Stückelberg procedure and dS in pure supergravity

2020 ◽  
Vol 476 (2237) ◽  
pp. 20200035 ◽  
Author(s):  
Silvia Nagy ◽  
Antonio Padilla ◽  
Ivonne Zavala
Keyword(s):  
Cosmological Constant ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Accelerated Expansion ◽  
Spontaneous Breaking ◽  
De Sitter ◽  
Expectation Value ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Natural Way

Understanding de Sitter space in supergravity—and string theory—has led to an intense amount of work for more than two decades, largely motivated by the discovery of the accelerated expansion of the Universe in 1998. In this paper, we consider a non-trivial generalization of unimodular gravity to minimal N = 1 supergravity, which allows for de Sitter solutions without the need of introducing any matter. We formulate a superspace version of the Stückelberg procedure, which restores diffeomorphism and local supersymmetry invariance. This introduces the goldstino associated with spontaneous breaking of supersymmetry in a natural way. The cosmological constant and gravitino mass are related to the vacuum expectation value of the components of a Lagrange multiplier imposing a super-unimodularity condition.

scholarly journals Unified emergence of energy scales and cosmic inflation

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Jisuke Kubo ◽  
Jeffrey Kuntz ◽  
Manfred Lindner ◽  
Jonas Rezacek ◽  
Philipp Saake ◽  
...  
Keyword(s):  
Scale Invariance ◽  
Planck Scale ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Spontaneous Breaking ◽  
Type I ◽  
Cosmic Inflation ◽  
Dynamical Generation ◽  
Majorana Neutrinos ◽  
Relic Abundance

Abstract In the quest for unification of the Standard Model with gravity, classical scale invariance can be utilized to dynamically generate the Planck mass MPl. However, the relation of Planck scale physics to the scale of electroweak symmetry breaking μH requires further explanation. In this paper, we propose a model that uses the spontaneous breaking of scale invariance in the scalar sector as a unified origin for dynamical generation of both scales. Using the Gildener-Weinberg approximation, only one scalar acquires a vacuum expectation value of υS ∼ (1016−17) GeV, thus radiatively generating $$ {M}_{\mathrm{P}1}\approx {\beta}_S^{1/2}{\upsilon}_S $$ M P 1 ≈ β S 1 / 2 υ S and μH via the neutrino option with right handed neutrino masses mN = yMυS ∼ 107 GeV. Consequently, active SM neutrinos are given a mass with the inclusion of a type-I seesaw mechanism. Furthermore, we adopt an unbroken Z2 symmetry and a Z2-odd set of right-handed Majorana neutrinos χ that do not take part in the neutrino option and are able to produce the correct dark matter relic abundance (dominantly) via inflaton decay. The model also describes cosmic inflation and the inflationary CMB observables are predicted to interpolate between those of R2 and linear chaotic inflationary model and are thus well within the strongest experimental constraints.

Mass hierarchies and scalar field self-couplings

1983 ◽  
Vol 61 (3) ◽  
pp. 415-427
Author(s):  
V. Elias ◽  
T. N. Sherry
Keyword(s):  
Scalar Field ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Large Mass ◽  
Mass Ratio ◽  
Abelian Gauge ◽  
Expectation Value ◽  
Tree Approximation ◽  
First Order ◽  
Large Mass Ratio

One (internal gauge boson) loop corrections to the scalar field self-couplings of a spontaneously broken Abelian gauge theory are shown to be independent of one loop shifts in mass (and vacuum expectation value) from tree approximation values, suggesting that stability of arbitrarily large mass ratios under perturbation theory may be possible under an appropriately chosen set of renormalization conditions. However, imposition of a large mass ratio is shown to lead to overly large first order corrections to scalar field self-couplings, independent of the choice of renormalization conditions.

scholarly journals T $$ \overline{T} $$-flow effects on torus partition functions

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Song He ◽  
Yuan Sun ◽  
Yu-Xuan Zhang
Keyword(s):  
Hamiltonian Formalism ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Partition Functions ◽  
Majorana Fermions ◽  
Dirac Fermions ◽  
Conformal Field Theories ◽  
First Order ◽  
Conformal Field ◽  
Flow Effects

Abstract In this paper, we investigate the partition functions of conformal field theories (CFTs) with the T$$ \overline{T} $$ T ¯ deformation on a torus in terms of the perturbative QFT approach. In Lagrangian path integral formalism, the first- and second-order deformations to the partition functions of 2D free bosons, free Dirac fermions, and free Majorana fermions on a torus are obtained. The corresponding Lagrangian counterterms in these theories are also discussed. The first two orders of the deformed partition functions and the first-order vacuum expectation value (VEV) of the first quantum KdV charge obtained by the perturbative QFT approach are consistent with results obtained by the Hamiltonian formalism in literature.

scholarly journals Linearized supergravity with a dynamical preferred frame

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Arthur Marakulin ◽  
Sergey Sibiryakov
Keyword(s):  
Lorentz Invariance ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Timelike Vector ◽  
Chiral Vector ◽  
Model Following ◽  
Superluminal Velocity ◽  
General Action ◽  
Spatial Rotations ◽  
Local Lorentz Invariance

Abstract We study supersymmetric extension of the Einstein-aether gravitational model where local Lorentz invariance is broken down to the subgroup of spatial rotations by a vacuum expectation value of a timelike vector field called aether. Embedding aether into a chiral vector superfield, we construct the most general action which describes dynamics of linear perturbations around the Lorentz-violating vacuum and is invariant under the linearized supergravity transformations. The analysis is performed both in the off-shell non-minimal superfield formulation of supergravity and in the “on-shell” approach invoking only physical component fields. The resulting model contains a single free coupling, in addition to the standard supergravity parameters. The spectrum of physical excitations features an enhanced on-shell gravity multiplet comprising four states with helicities 2, 3/2, 3/2 and 1 propagating with superluminal velocity. The remaining excitations propagate with the speed of light. We outline the observational constraints on the model following from its low-energy phenomenology.

scholarly journals QUANTUM EFFECTS IN A ROTATING SPACETIME

2002 ◽  
Vol 11 (05) ◽  
pp. 715-731 ◽  
Author(s):  
EUGEN RADU ◽  
DUMITRU ASTEFANESEI
Keyword(s):  
Scalar Field ◽  
Effective Action ◽  
Quadratic Field ◽  
Quantum Effects ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Expectation Value ◽  
Causality Violation ◽  
Field Fluctuations

The behavior of a arbitrary coupled quantum scalar field is studied in the background of the Gödel spacetime. Closed forms are derived for the effective action and the vacuum expectation value of quadratic field fluctuations by using ζ-function regularization. Based on these results, we argue that causality violation presented in this spacetime cannot be removed by quantum effects.

FERMION SPECTRA AND KM MATRICES IN A LEFT-RIGHT SYMMETRIC MODEL FROM CALABI-YAU STRING COMPACTIFICATION

1993 ◽  
Vol 08 (29) ◽  
pp. 5235-5263
Author(s):  
CHUICHIRO HATTORI ◽  
MASAHISA MATSUDA ◽  
TAKEO MATSUOKA ◽  
DAIZO MOCHINAGA
Keyword(s):  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Current Data ◽  
Fourth Generation ◽  
Spontaneous Breaking ◽  
Neutrino Masses ◽  
Symmetric Model ◽  
Seesaw Mechanism ◽  
Flavor Changing ◽  
O 10

We study a left-right symmetric type of the effective low-energy theory induced from the four-generation superstring model. The spontaneous breaking of the R-parity occurs through a nonzero vacuum expectation value (VEV) of the fourth generation right-handed sneutrino (νR). It is predicted that the lightest chargino is lighter than 113 GeV. By virtue of the seesaw mechanism we can explain the smallness of neutrino masses for three generations and the largeness of the fourth generation neutrino mass. The mixing in the color-singlet sector yields nontrivial KM matrices which bring about flavor-changing interactions. If we take νR=O(10 TeV ), our results are consistent with the current data except for the solar neutrino problem.

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