We study the Casimir effect in the classical geometry of two parallel conductive plates, separated by a distance $L$, for a Lorentz-breaking extension of the scalar field theory. The Lorentz-violating part of the theory is characterized by the term $λ\left( u \cdot \partial ϕ\right )^{2}$, where the parameter $λ$ and the background four-vector $u ^μ$ codify Lorentz symmetry violation. We use Green's function techniques to study the local behavior of the vacuum stress-energy tensor in the region between the plates. Closed analytical expressions are obtained for the Casimir energy and pressure. We show that the energy density $\mathcal{E}_{C}$ (and hence the pressure) can be expressed in terms of the Lorentz-invariant energy density $\mathcal{E}_{0}$ as follows \begin{align}
\mathcal{E}_{C} (L) = \sqrt{\frac{1-λu_{n} ^{2}}{1 + λu ^{2}}} \mathcal{E}_{0} (\tilde{L}) , \notag \end{align} where $\tilde{L} = L / \sqrt{1-λu_{n} ^{2}}$ is a rescaled plate-to-plate separation and $u_{n}$ is the component of $\vec{u}$ along the normal to the plates. As usual, divergences of the local Casimir energy do not contribute to the pressure.
This paper investigates the Casimir Energy modifications due to the Lorentz-violating CPT-even contribution in an extension of the scalar QED. We have considered the complex scalar field satisfying Dirichlet boundary conditions between two parallel plates separated by a small distance. An appropriate tensor parametrization allowed us to study the Casimir effect in three setups: isotropic, anisotropic parity-odd, and anisotropic parity-even. We have shown that the Lorentz-violating contributions promote increased Casimir energy for both the isotropic and anisotropic parity-odd configurations. H…
In this paper we consider a Lorentz-breaking extension of the theory for a real massive scalar quantum field in the region between two large parallel plates, with our manner to break the Lorentz symmetry is CPT-even, aether-like. For this system we calculated the Casimir energy considering different boundary conditions. It turns out to be that the Casimir energy strongly depends on the direction of the constant vector implementing the Lorentz symmetry breaking, as well as on the boundary conditions.
The standard model and general relativity are local Lorentz invariants. However it is possible that at Planck scale there may be a breakdown of Lorentz symmetry. Models with Lorentz violation are constructed using Standard Model Extension (SME). Here gravitational sector of the SME is considered to analyze the Lorentz violation in Gravitoelectromagnetism (GEM). Using the energy-momentum tensor, the Stefan-Boltzmann law and Casimir effect are calculated at finite temperature to ascertain the level of local Lorentz violation. Thermo Field Dynamics (TFD) formalism is used to introduce temperature…
Following a field-theoretical approach, we study the scalar Casimir effect upon a perfectly conducting cylindrical shell in the presence of spontaneous Lorentz symmetry breaking. The scalar field is modeled by a Lorentz-breaking extension of the theory for a real scalar quantum field in the bulk regions. The corresponding Green's functions satisfying Dirichlet boundary conditions on the cylindrical shell are derived explicitly. We express the Casimir pressure (i.e. the vacuum expectation value of the normal-normal component of the stress-energy tensor) as a suitable second-order differential o…
In this paper, we study the electromagnetic Casimir effects in the context of Lorentz symmetry violations. Two distinct approaches are considered: the first one is based on Horava-Lifshitz methodology, which explicitly presents a space-time anisotropy, while the second is a model that includes higher-derivatives in the field strength tensor and a preferential direction in the space-time. We assume that the electromagnetic field obeys the standard boundary conditions on two large parallel plates. Our main objectives are to investigate how the Casimir energy and pressure are modified in both Lor…
We determine the effect of Lorentz invariance violation in the vacuum energy and stress between two parallel plates separated by a distance $L$, in the presence of a massive real scalar field. We parametrize the Lorentz-violation in terms of a symmetric tensor $h^{\,μν}$ that represents a constant background. Through the Green's function method, we obtain the global Casimir energy, the Casimir force between the plates and the energy density in a closed analytical form without resorting to perturbative methods. With regards to the pressure, we find that $\mathcal{F}_c(L)=\mathcal{F}_0(\tilde{L}…
Violation of the Lorentz symmetry has important effects on physical quantities including field propagators. Therefore, in addition to the leading order, the sub-leading order of quantities may be modified. In this paper, we calculate the next to leading (NLO) radiative corrections to the Casimir energy in the presence of two perfectly conducting parallel plates for $ϕ^4$ theory with a Lorentz-breaking extension. We do the renormalization and investigate these NLO corrections for three distinct directions of the Lorentz violation; temporal direction, parallel and perpendicular to the plates.
In this paper I study the Casimir effect caused by a charged and massive scalar field that breaks Lorentz invariance in a CPT-even, aether-like manner. I investigate the case of a scalar field that satisfies Dirichlet or mixed (Dirichlet-Neumann) boundary conditions on a pair of very large plane parallel plates. The case of Neumann boundary conditions is straightforward and will not be examined in detail. I use the $ζ$-function regularization technique to study the effect of a constant magnetic field, orthogonal to the plates, on the Casimir energy and pressure. I investigate the cases of a ti…
The renormalization program in every renormalized theory should be run consistently with the type of boundary condition imposed on quantum fields. To maintain this consistency, the counterterms usually appear in the position-dependent form. In the present study, using such counterterms, we calculated the radiative correction to the Casimir energy for massive and massless Lorentz-violating scalar field constrained with Dirichlet boundary condition between two parallel plates in d spatial dimensions. In the calculation procedure, to remove infinities appearing in the vacuum energies, the box sub…
A Lorentz symmetry violation aether-type theoretical model is considered to investigate the Casimir effect and the generation of topological mass associated with a self-interacting massive scalar fields obeying Dirichlet, Newman and mixed boundary conditions on two large and parallel plates. By adopting the path integral approach we found the effective potential at one- and two-loop corrections which provides both the energy density and topological mass when taken in the ground state of the scalar field. We then analyse how these quantities are affected by the Lorentz symmetry violation and co…
We study the Casimir effect in the framework of Standard Model Extension (SME). Employing the weak field approximation, the vacuum energy density ε and the pressure for a massless scalar field confined between two nearby parallel plates in a static spacetime background are calculated. In particular, through the analysis of ε, we speculate a constraint on the Lorentz-violating term s00 which is lower than the bounds currently available for this quantity. After that, the correction to the pressure given by the gravitational sector of SME is presented. Finally, we remark that our outcome has an i…
One-Loop Correction to the Casimir Energy in Lorentz-Violating $ϕ^4$ Theory with Rough Membrane Boundaries
Department of Physics, Semnan Branch, Islamic Azad University, Semnan, Iran（伊斯兰阿扎德大学塞姆南分校物理系）；Energy and Sustainable Development Research Center, Semnan Branch, Islamic Azad University, Semnan, Iran（伊斯兰阿扎德大学塞姆南分校能源与可持续发展研究中心）
In this work I investigate the finite temperature Casimir effect due to a massive and charged scalar field that breaks Lorentz invariance in a CPT-even, aether-like way. I study the cases of Dirichlet and mixed (Dirichlet-Neumann) boundary conditions on a pair of parallel plates. I will not examine the case of Neumann boundary conditions since it produces the same results as Dirichlet boundary conditions. The main tool used in this investigation is the $ζ$-function technique that allows me to obtain the Helmoltz free energy and Casimir pressure in the presence of a uniform magnetic field perpe…
Fermionic Casimir effect in an axial Lorentz-violating background
Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México（墨西哥国立自治大学核科学研究所）；Universidade Estadual da Paraíba (UEPB), Centro de Ciências Exatas e Sociais Aplicadas (CCEA)（帕拉伊巴州立大学精确科学与社会科学中心）；Departamento de Física, Universidade Federal da Paraíba（帕拉伊巴联邦大学物理系）
We show that in the functional integral formalism the (finite) coefficient of the induced, Lorentz- and CPT-violating Chern-Simons term, arising from the Lorentz- and CPT-violating fermion sector, is undetermined.
This paper shows that the positive-energy and non-renormalization theorems of traditional supersymmetry survive the addition of Lorentz violating interactions. The Lorentz-violating coupling constants in theories using the construction of Berger and Kostelecky must obey certain constraints in order to preserve the positive energy theorem. Seiberg's holomorphic arguments are used to prove that the superpotential remains non-renormalized (perturbatively) in the presence of Lorentz-violating interactions of the Berger-Kostelecky type. We briefly comment on Lorentz-violating theories of the type c…
The CPT-even sector of the standard model extension amounts to extending Maxwell electrodynamics by a gauge invariant term of the form $- \frac{1}{4} (k _{F}) _{αβμν} F ^{αβ} F ^{μν}$, where the Lorentz-violating (LV) background tensor $(k _{F}) _{αβμν}$ possesses the symmetries of the Riemann tensor. The electrodynamics in ponderable media is still described by Maxwell equations in matter with modified constitutive relations which depend on the coefficients for Lorentz violation. We study the effects of this theory on the Casimir force between two semi-infinite ponderable media. The Fresnel c…
We identify a fairly general class of field configurations (of spins 0, 1/2 and 1) which preserve Lorentz invariance in effective field theories of Lorentz violation characterized by a constant timelike vector. These fields concomitantly satisfy the equations of motion yielding cubic dispersion relations similar to those found earlier. They appear to have prospective applications in inflationary scenarios.
The two-dimensional aether-superspace is constructed and the superfield techniques are applied to the study of dynamical generation of mass in the Lorentz-violating supersymmetric quantum electrodynamics in two dimensions of spacetime. It is shown that such model presents a dynamical generation of mass to the gauge aether-superfield and its dispersion relation has the structure similar of the CPT-even Lorentz-breaking models.
In this work we study the issue of gauge anomalies in Lorentz-violating QED. To do so, we opt to use the Becchi-Rouet-Stora-Tyutin formalism within the algebraic renormalization approach, reducing our study to a cohomology problem. Since this approach is independent of the renormalization scheme, the results obtained here are expected to be general. We find that the Lorentz-violating QED is free of gauge anomalies to all orders in perturbation theory.
We calculate the induced Lorentz- and CPT-violating Chern-Simons term arising from the Lorentz- and CPT-violating sector of quantum electrodynamics with a $b_μ\barψγ^μγ_5ψ$ term. The result to all orders in $b$ coincides with the previous linear-in-$b$ calulation by Chung and Oh [hep-th/9812132] as well as Jackiw and Kostelecký [Phys. Rev. Lett. {\bf 82}, 3572 (1999)], since all higher order terms vanish.
The role played by a Lorentz-violating term on the outcomes of kink scattering in the $ϕ^6$ model is investigated by using the Fourier spectral method. Impacts of the Lorentz-violating term on the critical velocities, the location of two-bounce windows, and the maximal values of various types of energy densities are analyzed. Some novel features of kink-antikink collisions are discussed. The interactions between three and four kinks are also considered.
We consider one-loop radiative corrections from Lorentz- and CPT- violating extended QED to address the specific problem of finding explicitly an effective action describing amplitude of photon triple splitting. We show that it is not possible to find a nonzero photon triple splitting effective action, at least by using the derivative expansion method (at zero external momenta), up to leading order in the Lorentz- and CPT- violating parameter.
In this paper we study the one- and two-loop contribution to the free energy in QED with the Lorentz symmetry breaking introduced via constant CPT-even Lorentz-breaking parameters at the high temperature limit. We find the impact of the Lorentz-violating term for the free energy and carry out a numerical estimation for the Lorentz-breaking parameter.
In this paper, we evaluate the Casimir energy and pressure for a massive fermionic field confined in the region between two parallel plates. In order to implement this confinement we impose the standard MIT bag boundary on the plates for the fermionic field. In this paper we consider a quantum field theory model with a CPT even, aether-like Lorentz symmetry violation. It turns out that the fermionic Casimir energy and pressure depend on the direction of the constant vector that implements the Lorentz symmetry breaking.
The finding of an explicit effective action describing amplitude of photon triple splitting is investigated through Krein space quantization and quantum metric fluctuation. Using the derivative expansion method, the one-loop radiative corrections from Lorentz- and CPT- violating extended Krein QED shows that it is not possible to find a nonzero effective action.
In this paper, we analyze the fermionic Casimir effects associated with a massless quantum field in the context of Lorentz symmetry violation approach based on Horava-Lifshitz methodology. In order to obtain these observables, we impose the standard MIT bag boundary condition on the fields on two large and parallel plates. Our main objectives are to investigate how the Casimir energy and pressure depend on the parameter associated with the breaking of Lorentz symmetry.
Assuming Lorentz symmetry is broken by some fixed vector background, we study the spinor electrodynamics modified by two dimension-five Lorentz-violating interactions between fermions and photons. The effective polarization and magnetization are identified from the modified Maxwell equations, and the theoretical consequences are investigated. We also compute the corrections to the relativistic energy levels of hydrogen atom induced by these Lorentz-violating operators in the absence and presence of uniform external fields in first-order perturbation theory. We find that the hydrogen spectrum i…
In this work, kink-antikink collision in a two-dimensional Lorentz-violating $ϕ^4$ model is considered. It is shown that the Lorentz-violating term in the proposed model does not affect the structure of the linear perturbation spectrum of the standard $ϕ^4$ model, and thus there exists only one vibrational mode. The Lorentz-violating term impacts, however, the frequency and spatial wave function of the vibrational mode. As a consequence, the well-known results on $ϕ^4$ kink-antikink collision will also change. Collisions of kink-antikink pairs with different values of initial velocities and Lo…
We derive the free energy of a Lorentz invariance violating (LIV) O(2) model, for which a non-vanishing commutator among it's momenta is supposed. Then we investigate the possible implications of such a matter field on the time evolution of a flat FRW universe at low and high temperatures.
In this work we present a class of traveling solitons in Lorentz-violating systems. In the case of Lorentz violating scenarios, it is usual to construct static solitonic configurations. Here it is shown that it is possible to construct some traveling solitons which, as it should be expected, can not be mapped into a static configuration by means of Lorentz boosts due to its explicit breaking. Furthermore, in the model studied, a complete set of solutions is obtained. The solutions present a critical behavior controlled by the choose of an arbitrary integration constant.
We examine the radiative corrections to an extension of the standard model containing a Lorentz-violating axial vector parameter. At second order in this parameter, the photon self-energy is known to contain terms that violate gauge invariance. Previously, this has been treated as a pathology, but it is also possible to take the gauge noninvariant terms at face value. These terms then make Lorentz-violating contributions to the photon mass, and directly measured limits on the photon mass can be used to set bounds on the Lorentz violation at better than the 10^-22 GeV level.
We investigate the occurrence of ambiguities for Lorentz-violating gravitational Chern-Simons term. It turns out that this term is accompanied by a coefficient depending on an undetermined parameter, due to an arbitrariness in the choice of the conserved current.
We search for novel Lorentz- and CPT-violating field theories, beyond those contained in the superficially renormalizable standard model extension. We find a new class of scalar field self-interactions which are nonpolynomial in form, involving arbitrarily high powers of the field. Many of these interactions correspond to nontrivial asymptotically free theories. These theories are stable if rotation invariance remains unbroken. These results indicate that certain forms of Lorentz violation, if they exist, may naturally be quite strong.
We have studied BPS vortices in a CPT-odd and Lorentz-violating Maxwell-Chern-Simons-Higgs (MCSH) electrodynamics attained from the dimensional reduction of the Carroll-Field-Jackiw-Higgs model. The Lorentz-violating parameter induces a pronounced behavior at origin (for the magnetic/electric fields and energy density) which is absent in the MCSH vortices. For some combination of the Lorentz-violating coefficients there always exist a sufficiently large winding number $n_{0}$ such that for all $% |n|\geq |n_{0}|$ the magnetic field flips its signal, yielding two well defined regions with oppos…
This paper presents divergent contributions of the radiative corrections for a Lorentz-violating extension of the scalar electrodynamics. We initially discuss some features of the model and extract the Feynman rules. Then we compute the one-loop radiative corrections using Feynman parametrization and dimensional regularization in order to evaluate the integrals. We also discuss Furry's theorem validity and renormalization in the present context.
In this paper the effective potential approach in quantum field theory is used in order to investigate self-interaction loop correction to the Casimir energy density and generation of topological mass for both massless and massive real scalar fields. It is assumed that the scalar field obeys a helix boundary condition. In addition, it is also considered a CPT-even aether-type violation of the Lorentz symmetry. In the absence of the Lorentz violation we obtain analytical expressions for the loop correction to the Casimir energy density and to the mass of the scalar field. The same expressions a…
The Casimir effect is one of the most direct manifestations of the existence of the vacuum quantum fluctuations, discovered by H. B Casimir in 1948. On the other hand, Lorentz invariance is one of the main and basic concepts in special relativity, which states that, the laws of physics are invariant under Lorentz transformation. In this work, we calculate the corrections imposed by LIV on Casimir effect (force). This may provide a direct probe to test LIV in nature.
In this work we make use of proper-time method to evaluate Schwinger effect in the presence of Lorentz-violating background fields. Specifically, we evaluate the one-loop effective Lagrangian in the presence of Lorentz-violating time-like vector background $b_μ$ and pseud-scalar $m_5$ for the pure electric case. The imaginary part of the effective Lagrangian is computed in order to calculate the Schwinger effect. Comments on phenomenology are also performed.
The standard forms of supersymmetry and supergravity are inextricably wedded to Lorentz invariance. Here a Lorentz-violating form of supergravity is proposed. The superpartners have exotic properties that are not possible in a theory with exact Lorentz symmetry and microcausality. For example, the bosonic sfermions have spin 1/2 and the fermionic gauginos have spin 1. The theory is based on a phenomenological action that is shown to follow from a simple microscopic and statistical picture.
We consider the role of the velocity in Lorentz-violating fermionic quantum theory, especially emphasizing the nonrelativistic regime. Information about the velocity will be important for the kinematical analysis of scattering and other problems. Working within the minimal standard model extension, we derive new expressions for the velocity. We find that generic momentum and spin eigenstates may not have well-defined velocities. We also demonstrate how several different techniques may be used to shed light on different aspects of the problem. A relativistic operator analysis allows us to study…
In theories with broken Lorentz symmetry, Cerenkov radiation may be possible even in vacuum. We analyze the Cerenkov emissions that are associated with the least constrained Lorentz-violating modifications of the photon sector, calculating the threshold energy, the frequency spectrum, and the shape of the Mach cone. In order to obtain sensible results for the total power emitted, we must make use of information contained within the theory which indicates at what scale new physics must enter.
The fermionic f coefficient in the Lorentz-violating standard model extension presents a puzzle. Thus far, no observable quantity that depends upon f has ever been found. We show that this is because f is actually unnecessary. It has absolutely no effects at leading order and can be completely absorbed into other coefficients of the theory by a redefinition of the field.
We calculate by the method of dimensional regularization and derivative expansion the one-loop effective action for a Dirac fermion with a Lorentz-violating and CPT-odd kinetic term in the background of a gauge field. We show that this term induces a Chern-Simons modification to Maxwell theory. Some related issues are also discussed.
S-matrix amplitudes for the electron-electron scattering are calculated in order to verify the quantum equivalence of dual models. We used an extended Quantum Electrodynamics with CPT-even Lorentz-violating kinetic and mass terms, which was used in a process of gauge embedding, known as Noether dualizationn method (NDM), in order to generate its gauge-invariant dual model. The physical equivalence was established at tree-level and the cross section was calculated to second order in the Lorentz-violating parameter.
