Annals of Physics最新文献

In a recent study (Sadeghi and Noori Gashti, 2024) the so-called Reissner–Nordström (RN) black hole surrounded by perfect fluid dark matter (PFDM) has been investigated. Here in this Letter, we prove that technically such a black hole does not exist in the context of Maxwell’s linear theory coupled minimally to a PFDM. Furthermore, it is shown that this black hole is the result of nonlinear corrections to the linear Maxwell’s Lagrangian in the Einstein–Maxwell theory. The energy–momentum tensor is split into Maxwell’s linear theory and a correction term. The latter i.e., the correction part of the energy–momentum tensor represents an anisotropic dark energy. This result brings the question if nonlinear electrodynamics can be the source of dark matter/energy.

After many years of efforts, the first nonlinearly charged rotating black hole has been finally reported by García-Diaz in two recent works. This is an important result that was pending in General Relativity since nonlinear generalizations of the Kerr–Newman solution were not yet known. Unfortunately, the Lagrangian supporting this configuration cannot be expressible in terms of the standard invariants using elementary functions. In the present work we circumvent this problem by using the formulations of nonlinear electrodynamics in terms of mixed electromagnetic eigenvalues, introduced by Salazar, García-Diaz, and Plebański almost four decades ago. In doing so, we prove that the underlying theory becomes fully determined, and hence the new nonlinearly charged stationary axisymmetric spacetimes found correspond to exact solutions of a well-defined self-gravitating nonlinear electrodynamics whose fundamental structural functions are provided here.

We have investigated the decoherence induced by the primordial graviton, using the influence functional method, to show whether this method is still effective in detecting graviton if the initial state is not a Bunch–Davies vacuum but rather a minimum uncertainty state. This minimum uncertainty condition allows the initial state of the primordial graviton to be an entanglement state between the polarization or, more generally, a superposition state between a vacuum and that entanglement. Both of those states have a non-classical correlation between the two polarization modes. We found that this method is still effective for detecting gravitons if the density matrix of the initial state does not have non-diagonal elements, where the maximum decoherence time is about 20 s, and the dimensions of the interferometer could be reduced if the total graviton increases.

We explore how the electric conductivity and associated relaxation time are modified near the QCD critical point and the phase transition to a color superconducting phase using the two-flavor Nambu–Jona–Lasinio model with finite current quark masses. We give a comprehensive account of the nature of the soft modes associated with these phase transitions and how they affect the photon self-energy when the system approaches these phase transitions in a combined way with an emphasis on the common and different aspects in the two transitions. The formalism developed for describing the paraconductivity in metallic superconductors is used for the analysis of the photon self-energy. We show that the transport coefficients calculated from the self-energy show anomalous enhancements in both cases with different critical exponents for the individual transitions. We briefly discuss the possibility of detecting the enhancements in the relativistic heavy-ion collisions in the present and future facilities.

In this paper we present a new identity to associate the conservation laws of stress–energy tensor with the field equations in Yang–Mills theory. The Lorentz force is included with a consistent formulation as in Maxwell theory.

This study aims to analyze the effects of modified gravity via anti-curvature tensor on a gravitational model set up within a 5-dimensional space–time, focusing on brane-world scenarios. The anti-curvature tensor introduces innovative configuration that is equal to the inverse of the Ricci tensor. In this analysis, we consider $f(R,A)=(R+\alpha A)$, where the coupling parameter $\alpha$ influences both vacuum regions outside the brane and the core region within it. Through analysis, this study uncovers alterations in fermion localization, particularly impacting left-chirality fermion. To quantify fermion localization, probabilistic metrics such as Shannon entropy and relative probability are employed, demonstrating a heightened level of certainty as $\alpha$ values increase. These findings shed significant light on the dynamics of extra-dimensional models, providing valuable insights into the realms of particle physics and cosmology.

In this work, we explore the inflationary dynamics induced by small fluctuations on the Skyrme brane, characterized by a time-dependent perturbative function $\tilde{\varphi }$. In the low-energy regime, the model successfully reproduces standard inflation, with a potential term dictated by the Skyrmion at the brane. Gravity localization is achieved at the brane, and the lowest energy scale is established at the asymptotic boundary. The model demonstrates the capability to emulate standard inflation dynamics, resembling ${\tilde{\varphi }}^4$ potential characteristics under certain conditions. At higher energy regions, the behaviour of $\tilde{\varphi }$ is contingent upon the Skyrme term coupling constant $\lambda$, influencing reheating phases. The wave-like nature of fluctuations allows for energy transfer, resulting in a possibly lower reheating temperature. We also discuss the prospect of $\lambda$ changing sign during inflation, presenting a non-standard coupling dependent on the matter field.

We study a family of separable potentials with and without added contact interactions by solving the associated Lippmann–Schwinger equation with two coupled partial waves. The matching of the resulting amplitude matrix with the effective-range expansion is studied in detail. When a counterterm is included in the potential we also carefully discuss its renormalization. Next, we use the matrix $N/D$ method and study whether the amplitude matrices from the potentials considered admit an $N/D$ representation in matrix form. As a novel result we show that it is typically not possible to find such matrix representation for the coupled partial-wave case. However, a separate $N/D$ representation for each coupled partial wave — a valid option known in the literature — is explicitly implemented and numerically solved in cases where the matrix $N/D$ method is unavailable.

We study scalar quasinormal modes in a D3/D7 system holographically dual to a quantum field theory with chiral symmetry breaking at finite temperature. From the bottom-up approach, we consider a nontrivial dilaton profile which is responsible for the anomalous dimension of the quark condensate. It depends on a new parameter $q$ in the model. By varying this parameter, we study the behavior of the massive and massless scalar quasinormal modes. The numerical method that we use is the spectral method, and we find that there is no pure imaginary mode for the massless case but it appears by increasing the parameter $q$. It is known that this mode becomes tachyonic for massive cases. Then we turn on a pseudoscalar field and using a simple ansatz study its effect on the quasinormal modes of the scalar field. By varying the parameter of the nontrivial dilaton profile in the model, we qualitatively study quasinormal modes in walking theories.

We consider a massless and minimally coupled self interacting quantum scalar field theory in the inflationary de Sitter background of dimension four. The self interaction potential is taken to be either quartic, $\lambda {\varphi }^4/4!$, or quartic plus cubic, $\lambda {\varphi }^4/4!+\beta {\varphi }^3/3!$ ($\lambda >0$). We compute the four and three point vertex functions up to two loop. The purely local or partly local part of these renormalised loop corrected vertex functions grow unboundedly after sufficient number of de Sitter $e$-foldings, due to the appearances of secular logarithms. We focus on the purely local part of the vertex functions and attempt a resummation of them in terms of the dynamically generated mass of the scalar field at late times. Such local logarithms have sub-leading powers compared to the non-local leading ones which can be resummed via the stochastic formalism. The variation of these vertex functions are investigated with respect to the tree level couplings numerically. Since neither the secular effect, nor the dynamical generation of field mass is possible in the Minkowski spacetime, the above phenomenon has no flat spacetime analogue. We have also compared our result with the ones that could be found via the recently proposed renormalisation group techniques. All these results suggest that at late times the value of the non-perturbative vertex function should be less than the tree level coupling.