We show that $CPT$-even aetherlike Lorentz-breaking actions, for the scalar and electromagnetic fields, are generated via their appropriate coupling to spinor in three, four, five space-time dimensions. Besides, we also terms field can be as a consequence of same couplings. discuss dispersion relations theories with find tree-level effective (Breit) potential fermion scattering one-loop corresponding action field.

We consider a metric-affine extension to the gravitational sector of Standard Model for Lorentz-violating coefficients $u$ and ${s}^{\ensuremath{\mu}\ensuremath{\nu}}$. The general results, which are applied specific model called bumblebee gravity, obtained. A Schwarzschild-like solution, incorporating effects Lorentz symmetry breaking through coefficient $X=\ensuremath{\xi}{b}^{2}$, is found. Furthermore, complete study geodesic trajectories particles accomplished in this background,...

Abstract Within the framework of spontaneous Lorentz symmetry breaking (LSB), we consider a metric-affine generalization gravitational sector Standard Model Extension (SME), including Lorentz-violating (LV) coefficients u and s μν . In this model, derive modified Einstein field equations in order to obtain new axisymmetric vacuum spinning solution for particular bumblebee's profile. Such has remarkable property incorporating effects LSB through LV dimensionless parameter X = ξb 2 , with ξ is...

In this work, we calculate the deflection angle of light in a spacetime that interpolates between regular black holes and traversable wormholes, depending on free parameter metric. Afterwards, angular is substituted into lens equations which allows to obtain physically measurable results, such as position relativistic images magnifications.

This work deals with braneworld scenarios generalized gravity. We investigate models where the potential of scalar field is polynomial or nonpolynomial. obtain exact and approximated solutions for field, warp factor energy density, in complex scenario no restriction on curvature. In particular, we describe case brane may split, engendering internal structure, splitting caused by same parameter that controls deviation from standard

In this paper, we describe the perturbative generation of higher-derivative Lorentz-breaking terms for gauge field, that is, Myers-Pospelov term and Carroll-Field-Jackiw term. These are explicitly calculated in one-loop approximation shown to be finite ambiguous.

In this paper we consider a Lorentz-breaking extension of the theory for real massive scalar quantum field in region between two large parallel plates, with our manner to break Lorentz symmetry is CPT-even, aether-like. For system calculated Casimir energy considering different boundary conditions. It turns out be that strongly depends on direction constant vector implementing breaking, as well

In this paper, we investigate the thermal effect on Casimir energy associated with a massive scalar quantum field confined between two large parallel plates in CPT-even, aether-like Lorentz-breaking theory. order to do that, consider nonzero chemical potential for assumed be equilibrium at some finite temperature. The calculations of energies are developed by using Abel–Plana summation formula, and corresponding results analyzed several asymptotic regimes parameters system, like mass, separations

We consider the space-time metric generated by a global monopole in an extension of general relativity (GR) form $f(\mathcal{R})=\mathcal{R}\ensuremath{-}\ensuremath{\lambda}{\mathcal{R}}^{2}$. The theory is formulated metric-affine (or Palatini) formalism, and exact analytical solutions are obtained. For $\ensuremath{\lambda}<0$, one finds that solution has same characteristics as Schwarzschild black hole with charge Einstein's GR. $\ensuremath{\lambda}>0$, instead, more closely related to...

This paper is devoted to study the thermal aspects of a photon gas within context Planck-scale-modified dispersion relations. We spectrum radiation and correction \textit{Stefan$-$Boltzmann} law in different cases when Lorentz symmetry no longer preserved. Explicitly, we examine two models CPT$-$even CPT$-$odd sectors respectively. To do so, three distinct scenarios Universe are considered: Cosmic Microwave Background (CMB), electroweak epoch, inflationary era. Moreover, equations state...

Abstract We consider the metric-affine formulation of bumblebee gravity, derive field equations, and show that connection can be written as Levi-Civita a disformally related metric in which determines disformal part. As consequence, gets coupled to all other matter fields present theory, potentially leading nontrivial phenomenological effects. To explore this issue we compute post-Minkowskian, weak-field limit study resulting effective theory. In scenario, couple scalar spinorial metric,...

We consider the metric-affine formulation of bumblebee gravity, derive field equations, and show that connection can be written as Levi-Civita a disformally related metric in which determines disformal part. As consequence, gets coupled to all other matter fields present theory, potentially leading nontrivial phenomenological effects. To explore this issue we compute weak-field limit study resulting effective theory. In scenario, couple scalar spinorial which, besides zeroth-order...

Abstract The metric-affine bumblebee model in the presence of fermionic matter minimally coupled to connection is studied. We show that admits an Einstein frame representation which sector described by a non-minimal Dirac action without any analogy literature. Such terms involve unconventional couplings between and fermion field. then rewrite quadratic basis 16 matrices order identify coefficients for Lorentz/CPT violation all orders coupling ξ . exact result determinant frame, including ,...

In this study, we investigate the signatures of a non-commutative black hole solution. Initially, calculate thermodynamic properties system, including entropy, heat capacity, and Hawking radiation. For latter quantity, employ two distinct methods: surface gravity topological approach. Additionally, examine emission rate remnant mass within context. Remarkably, lifetime hole, after reaching its final state due to evaporation process, is expressed analytically up grey-body factor. We estimate...

Within the superfield approach, we formulate supersymmetric ether-like Lorentz-breaking models, both in three- and four-dimensional cases.Received 27 June 2012DOI:https://doi.org/10.1103/PhysRevD.86.065035© 2012 American Physical Society

Here, we consider a gravity theory involving spontaneous Lorentz symmetry breaking called the bumblebee model. We show that, at certain values of field, Gödel metric is consistent within this theory.

In this paper, we formulate a theory of the second-rank antisymmetric (pseudo)tensor field minimally coupled to spinor, calculate one-loop effective potential field, and, explicitly, demonstrate that it is positively defined and possesses continuous set minima, both for tensor pseudotensor cases. Therefore, our model turns out display dynamical Lorentz symmetry breaking. We also argue that, contrarily derivative coupling use here, derivative-free couplings spinor do not generate thus allow

Abstract Radiative corrections in Lorentz violating (LV) models have already received a lot of attention the literature recent years, with many instances where LV operator one sector Standard Model Extension (SME) generates, via loop corrections, coefficients photon sector, which is probably most understood and well constrained part SME. In these works, however, now standard notation SME not used, can obscure comparison different results, their possible phenomenological relevance. this work,...

In this paper, we develop a thermal description for photon modes within the context of bouncing universe. Within study, start with Lorentz-breaking dispersion relation which accounts modified Friedmann equations bounce solution. We calculate spectral radiance, entropy, Helmholtz free energy, heat capacity and mean energy. Nevertheless, latter two ones turn out to contribute only in trivial manner. Furthermore, one intriguing aspect gives rise to: some configurations [Formula: see text],...

A four-dimensional Lorentz-breaking non-Abelian Chern-Simons-like action is generated as a one-loop perturbative correction via an appropriate coupling of the gauge field to spinor field. This term shown be regularization dependent, but nevertheless it can found unambiguously in different schemes at zero and finite temperature.

Within the superfield method, we extend formulation of Lorentz-breaking aether superspace for supergauge theories, in both three- and four-dimensional cases.Received 14 May 2013DOI:https://doi.org/10.1103/PhysRevD.88.045022© 2013 American Physical Society

We describe a Horava-Lifshitz-like reformulated four-fermion Gross-Neveu model describing the dynamics of two-component spinors in (2+1)-dimensional space-time. Within our study, we introduce Lagrange multiplier, study gap equation (including finite temperature case) which turns out to display essentially distinct behaviors for even and odd values critical exponent z, show that dynamical parity breaking occurs only z. demonstrate any there exists at disappears. Besides this, obtain effective...