arXiv subjects

Hugo García-Compeán

Publications and source records attributed to Hugo García-Compeán.

9 recordsLinked to original sources

arXiv2026

On modified Hawking radiation under quantum gravity effects in the fermion sector

In this letter, after briefly discussing Hawking radiation (HR) as quantum tunneling, we emphasize that special care must be taken when computing temperature corrections in the presence of Lorentz invariance violation (LIV), particularly by ensuring consistency between the modified dispersion relation and the gamma matrix structure used to describe fermions that are tunneling. We present a consistent implementation of such corrections in static, spherically symmetric black hole (BH) spacetimes. As the conserved Killing energy $ω= p_μξ^μ$ in a stationary, asymptotically flat spacetime corresponds to the particle's energy measured by an observer at infinity, one might expect LIV terms that increase (decrease) the energy of a free particle, as defined in the local spacetime frame, to lead to a corresponding increase (decrease) in the Hawking temperature. We discuss the conditions under which this expectation holds. We also determined the changes in Bekenstein-Hawking entropy for Schwarzschild-like BHs, including corrections from LIV scenarios.

gr-qc↗

arXiv2026

Surface Variables Description of Axion Topological Materials

We study the response of axion topological materials under the presence of external static electric and magnetic fields. We focus on the macroscopic quasi-static magnetoelectric response of topological insulators. We use techniques based on surface variables that have been previously employed in soft condensed matter problems for the description of heterogeneous systems composed of multiple homogeneous materials. A complete description of the whole system is written in terms of surface degrees of freedom, which in this case correspond to effective surface charge and surface current densities. We obtain a set of integral equations satisfied by these variables. We present exact analytic solutions for axial-symmetric cases. We develop a numerical method for the solution of the integral equations by means of a boundary finite element method. We apply the numerical method to topological insulators with different geometries such as spheres, hollow spheres and toroidal surfaces. We show that that a variational principle can be used to recover the surface variables equations.

cond-mat.mtrl-sci↗

arXiv2026

Kerr-Schild solutions in Multigravity and the Classical Double Copy

We explore the multimetric theory of gravitation, also known as multigravity. We derive additional new exact solutions for the theory in proportional Kerr-Schild and double Kerr-Schild forms. We extend several solutions from the theory of General Relativity, characterized by a constant Ricci scalar in single and double Kerr-Schild forms, to derive solutions in the multi-gravity context. We also examine and extend the classical double copy relations that can be constructed out from these solutions in multigravity exploring the dynamics of the single copy and zero copy fields.

gr-qc↗

arXiv2025

Weyl double copy in bimetric massive gravity

The Weyl double copy formalism, which relates the Weyl spinor with the square of the field strength, is studied in the context of Hassan-Rosen bigravity for stationary and time-dependent solutions. We consider the dyonic Kerr-Newman-(A)dS solution and the Plebański-Demiański metric in the context of bigravity. These solutions are studied in the Weyl double copy both with matter independently coupled and show that no massive modes are present in the Weyl spinor. The equations of motion for the gauge and scalar fields are those of Maxwell equations coupled to an external source, and massless Klein-Gordon equations with a conformal curvature term and an external source, all of them consistent with general relativity. For wave solutions, massive modes are manifest in the Weyl spinor and a formulation in bigravity for these massive modes is proposed. The resulting equations of motion are Proca equations with a conformal term and massive Klein-Gordon equations. In the case of the matter contributions for waves, we show how the resonance mass is present in equations of motion of the fields obtained from the Weyl double copy. The solutions studied are written in a Kerr-Schild form, connecting with the Kerr-Schild double copy.

gr-qc↗

arXiv2024

Plebański-Demiański solutions in bigravity and Kerr-Schild double copy relations using an effective metric

In this work a formalism for proportional generalized double Kerr-Schild ansatz in bigravity is considered, where both metrics are coupled to matter. We study time-dependent and stationary solutions in the framework of the Kerr-Schild classical double copy and obtain the classical Kerr-Schild for the double, single and zeroth copy equations. For the time-dependent case, we use AdS waves solutions in bigravity previously studied in the literature. For the stationary case, we discuss a kind of Plebański-Demiański solutions in bigravity which permit different masses, NUT parameters, electric and magnetic charges, while the kinematical parameters are the same, and the cosmological constants related. These solution is presented in Plebański coordinates, and it is noticed that in these coordinates the description simplifies the classical double copy equations allowing a clearer interpretation in terms of the defined fields. We present and interpret some cases for these solutions for the separate matter sector and using the effective metric.

gr-qc↗

arXiv2023

Non-Abelian T-dualities in Two Dimensional $(0,2)$ Gauged Linear Sigma Models

Two dimensional gauged linear sigma models(GLSMs) with $(0,2)$ supersymmetry and $U(1)$ gauge group possesing global symmetries are considered. For the case obtained as a reduction from the $(2,2)$ supersymmetric GLSM, we find the Abelian T-dual, comparing with previous studies. Then, the Abelian T-dual model of the pure $(0,2)$ theory is found. Instanton corrections are also discussed in both situations. In the cases under study we explore the vacua for the scalar potential and we analyse the target space geometry of the dual model. A model with gauge symmetry $U(1)\times U(1)$ is also discussed as precursor of an interesting example with non-Abelian global symmetry. Non-Abelian T-dualization of $U(1)$ $(0,2)$ $2d$ GLSMs is implemented for models which arise as a reduction from $(2,2)$ supersymmetry; we study a concrete model with $U(1)$ gauge symmetry and $SU(2)$ global symmetry. It is shown that for a positive definite scalar potential, the dual vacua to $\mathbb{P}^1$ constitutes a disk. Instanton corrections to the superpotential are obtained and shown to be encoded in a shifting of the holomorphic function ${E}$. We conclude by analyzing an example with $SU(2)\times SU(2)$ global symmetry and we obtain that the space of dual vacua to $\mathbb{P}^1\times \mathbb{P}^1$ consists of two copies of the disk, also for the case of positive definite potential. Here we are able to fully integrate the equations of motion leading to non-Abelian duality, improving with respect to previous $(2,2)$ studies.

hep-th↗

arXiv2021

On the topological and crosscap entropies in non-oriented RCFTs

We establish a relation between the boundary and the topological entropies for the conformal minimal models in some of the simplest models of the unitary A-A series. We show that in these models the boundary entropy is a difference of topological entropies. Furthermore, we define the crosscap entropy as the analog to the boundary entropy in non-oriented theories. The crosscap entropy is defined as the logarithm of the degeneracy of the ground state due to the presence of crosscaps and it can be expressed in terms of the crosscap coefficients. This crosscap entropy has not an explicit relation to the topological entropy as the boundary entropy. However, we propose a new quantity, $\hat S = \ln P_{0i}$ defined in terms of the modular transformation $P$ between the open and closed channel of the Möbius partition function. With this quantity, the crosscap entropy can be regarded as a difference of entropies, very similar to the boundary entropy. We also compute the left-right entanglement entropy (LREE) for crosscap states and we express it in terms of $\hat S$. An explicit example of the LREE of the crosscap state in Wess-Zumino-Witten is carried out

hep-th↗

arXiv2020

New heavenly double copies

The double copy relates scattering amplitudes and classical solutions in Yang-Mills theory, gravity, and related field theories. Previous work has shown that this has an explicit realisation in self-dual YM theory, where the equation of motion can be written in a form that maps directly to Plebański's heavenly equation for self-dual gravity. The self-dual YM equation involves an area-preserving diffeomorphism algebra, two copies of which appear in the heavenly equation. In this paper, we show that this construction is a special case of a wider family of heavenly-type examples, by (i) performing Moyal deformations, and (ii) replacing the area-preserving diffeomorphisms with a less restricted algebra. As a result, we obtain a double-copy interpretation for hyper-Hermitian manifolds, extending the previously known hyper-Kähler case. We also introduce a double-Moyal deformation of the heavenly equation. The examples where the construction of Lax pairs is possible are manifestly consistent with Ward's conjecture, and suggest that the classical integrability of the gravity-type theory may be guaranteed in general by the integrability of at least one of two gauge-theory-type single copies.

hep-th↗

arXiv2015

Uncertainty relations in quantum optics. Is the photon intelligent?

The Robertson -- Schrödinger, Heisenberg -- Robertson and Trifonov uncertainty relations for arbitrary two functions $f_{1}$ and $f_{2}$ depending on the quantum phase and the number of photons respectively, are given. Intelligent states and states which minimize locally the product of uncertainties $(Δf_{1})^{2}\cdot (Δf_{2})^{2}$ or the sum $(Δf_{1})^{2}+(Δf_{2})^{2}$ are investigated for the cases $f_{1}=ϕ,\exp{(iϕ)}, \exp{(-iϕ)}, \cosϕ, \sinϕ$ and $f_{2}=n$.

quant-ph↗