Annals of Physics最新文献

In this work, we consider a propagating scalar field on Kaluza–Klein-type cosmological background. It is shown that this geometrical description of the Universe resembles – from a Hamiltonian standpoint – a damped harmonic oscillator with mass and frequency, both time-dependents. In this scenario, we construct the squeezed coherent states (SCSs) for the quantized scalar field by employing the invariant operator method of Lewis–Riesenfeld (non-Hermitian) in a non-unitary approach. The non-classicality of SCSs has been discussed by examining the quadrature squeezing properties from the uncertainty principle. Moreover, we compute the probability density, which allows us to investigate whether SCSs can be used to seek traces of extra dimensions. We then analyze the effects of the existence of supplementary space on cosmological particle production in SCSs by considering different cosmological eras.

In this article, we study the black hole evaporation process and shadow property of the Tangherlini-Reissner-Nordström (TRN) black holes. The TRN black holes are the higher-dimensional extension of the Reissner-Nordström (RN) black holes and are characterized by their mass $M$, charge $q$, and spacetime dimensions $D$. In higher-dimensional spacetime, the black hole evaporation occurs rapidly, causing the black hole’s horizon to shrink. We derive the rate of mass loss for the higher-dimensional charged black hole and investigate the effect of higher-dimensional spacetime on charged black hole shadow. We derive the complete geodesic equations of motion with the effect of spacetime dimensions $D$. We determine impact parameters by maximizing the black hole’s effective potential and estimate the critical radius of photon orbits. The photon orbits around the black hole shrink with the effect of the increasing number of spacetime dimensions. To visualize the shadows of the black hole, we derive the celestial coordinates in terms of the black hole parameters. We use the observed results of M87 and Sgr A${}^{\ast }$ black hole from the Event Horizon Telescope and estimate the angular diameter of the charge black hole shadow in the higher-dimensional spacetime. We also estimate the energy emission rate of the black hole. Our finding shows that the angular diameter of the black hole shadow decreases with the increasing number of spacetime dimensions $D$.

In this work, we undertake a perturbative analysis of the topological non-Abelian Chern–Simons-Wong model with the aim to explicitly construct the second-order on-shell action. The resulting action is a topological quantity depending solely on closed curves, so it correspond to an analytical expression of a link invariant. Additionally, we construct an Abelian model that reproduces the same second-order on-shell action as its non-Abelian Chern–Simons-Wong counterpart so it functions as an intermediate model, featuring Abelian fields generated by currents supported on closed paths. By geometrically analyzing each term, we demonstrate that this topological invariant effectively detects the knotting of a four-component link.

In this study, we investigate the behavior of ModMax-de Sitter black holes when perturbed by massless neutral scalar fields. Specifically, we analyze how the relaxation time, defined as the inverse of the fundamental imaginary frequency, varies with respect to two key parameters: the cosmological constant and the nonlinear parameter characterizing the ModMax theory. We explore scenarios both with and without a cosmological constant, focusing on the static charged ModMax black hole configuration. Our results reveal dependencies between the relaxation time and the nonlinear parameter, shedding light on the dynamical properties of these black hole systems. We also show the validity of WKB approximation under consideration.

The asymptotic strong-coupling behavior as well as the exact critical exponents from scalar field theory even for the simplest case of $1+1$ dimensions have not been obtained yet. Hagen Kleinert has linked both critical exponents and strong coupling parameters to each other. He used a variational technique ( back to kleinert and Feynman) to extract accurate values for the strong coupling parameters from which he was able to extract precise critical exponents. In this work, we suggest a simple method of using the effective potential ( low order) to obtain exact values for the strong-coupling parameters for the ${\varphi }^4$ scalar field theory in $0+1$ and $1+1$ space–time dimensions. For the $0+1$ case, our results coincide with the well-known exact values already known from literature while for the $1+1$ case we test the results by obtaining the corresponding exact critical exponent. As the effective potential is a well-established tool in quantum field theory, we expect that the results can be easily extended to the most important three dimensional case and then the dream of getting exact critical exponents is made possible.

This paper focuses on additional inspections concerning the fermionic sector of the Standard Model Extension (SME). In this context, our main effort in this contribution is to investigate effects of Lorentz-symmetry violation (LSV) on the Klein Paradox, the Zitterbewegung and its phenomenology in connection to Condensed Matter Physics, Atomic Physics, and Astrophysics. Finally, we discuss a particular realization of LSV in the Dirac equation, considering an asymmetry between space and time due to a scale factor present in the linear momentum of the fermion, but which does not touch its time derivative. We go further and extend the implications of this asymmetry in the situation the scale factor becomes space–time dependent to compute its influence on the kinematics of the Compton effect with the extended dispersion relation for the fermion that scatters the photon.

We consider the dynamical Morris–Thorne metric with radiating heat flow. By matching the interior Morris–Thorne metric with an exterior Vaidya metric we trace out the collapse solutions for the corresponding spherically symmetric inhomogeneous distribution of matter. The solutions obtained are broadly of four different types, giving different end state dynamics. Corresponding to three of the solutions we elaborate the collapsing dynamics of the Morris–Thorne type evolving wormhole. We show that for all those cases where collapse upto zero proper volume is obtained in finite time, the ensuing singularity is always a black hole type. However our solutions can also show other end states, like oscillating wormhole-black hole pair or infinite time contracting universe or a conformal past matter dominated universe. In all the cases we have worked out the background dynamics and physics of the solution. All our solutions are illustrated with appropriate graphical descriptions.

This study extends two phenomenological models of dark energy within the framework of Finsler–Randers space–time, accommodating anisotropies. The models consider the cosmological constant $\Lambda$ in two scenarios: one where $\Lambda$ is proportional to the second time derivative of the scale factor $\ddot{a}$, and another where it varies with the matter-energy density $\rho$. Earlier, such $\Lambda$-decaying cosmologies were proposed to address long-standing cosmological constant problems. However, following the discovery of late-time cosmic acceleration, the focus shifted to modeling dark energy. Since $\Lambda$ is widely viewed as the most significant and suitable candidate for driving cosmic acceleration, it is worthwhile to revisit the phenomenological approach in this context. This work uses this approach to find solutions for the scale factor $a\left(t\right)$ and other geometrical and physical parameters. Additionally, we analyze the evolution of density parameters ${\Omega }_m$, ${\Omega }_{\Lambda }$, and ${\Omega }_{\kappa }$, representing matter, dark energy, and curvature, from early to late times. The phenomenological approach is employed to solve the field equations, with model parameters constrained using recent observational data, yielding ranges consistent with observations. The solutions converge to the $\Lambda$CDM cosmology at early and late times. The added complexity introduced by Finsler–Randers geometry enhances accuracy compared to analogous solutions in Riemannian space–time.

Traversable wormholes require exotic matter for stability, challenging their existence. Quantum mechanics offers a potential solution via the Casimir effect, which generates negative energy densities. In this study, we examine this interaction using two maximally localized quantum state models: the Kempf, Mangano, and Mann (KMM) model and the Detournay, Gabriel, and Spindel (DGS) model, incorporating Generalized Uncertainty Principle (GUP) corrections. We start by deriving the field equations for a generic $f(R,L_m)$ function, assuming a static and spherically symmetric Morris-Thorne wormhole metric. We then consider two specific gravity models: a linear model $f(R,L_m)=\frac{R}{2}+\alpha L_m$ and a nonlinear model $f(R,L_m)=\frac{R}{2}+L_m^n$, where $\alpha$ and $n$ are free parameters. Using the GUP-corrected Casimir effect, we derive the shape functions for these wormholes and investigate their existence. Next, we analyze the obtained wormhole solutions for each scenario, assessing the energy conditions at the wormhole throat with radius $r_0$. Our findings indicate that, for some arbitrary quantities, classical energy conditions are violated at the wormhole throat, highlighting the significant influence of GUP parameters on the geometry and physical properties of wormholes. Additionally, we explore the behavior of the equation of state (EoS) for each model. We further investigate the stability of the KMM and DGS wormhole solutions by applying the Tolman–Oppenheimer–Volkoff (TOV) equation. Finally, we use the volume integral quantifier to determine the amount of exotic matter required near the wormhole throat for both models, providing a comprehensive understanding of the exotic matter distribution necessary for maintaining wormhole stability.