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A new exactly solvable case in strong-field quantum electrodynamics with a time-dependent external electric field is presented. The corresponding field is given by an analytic function, which is asymmetric (in contrast to Sauter-like…

High Energy Physics - Theory · Physics 2021-10-13 A. I. Breev , S. P. Gavrilov , D. M. Gitman , A. A. Shishmarev

Unimodular gravity is an appealing approach to address the cosmological constant problem. In this scenario, the vacuum energy density of quantum fields does not gravitate and the cosmological constant appears merely as an integration…

General Relativity and Quantum Cosmology · Physics 2020-07-03 Cristóbal Corral , Norman Cruz , Esteban González

In a previous paper, a bound on the negative energy density seen by an arbitrary inertial observer was derived for the free massless, quantized scalar field in four-dimensional Minkowski spacetime. This constraint has the form of an…

General Relativity and Quantum Cosmology · Physics 2009-10-28 L. H. Ford , Thomas A. Roman

The behaviour of a massive, non-interacting and non-minimally coupled quantised scalar field in an expanding de Sitter background is investigated by solving the field evolution for an arbitrary initial state. In this approach there is no…

General Relativity and Quantum Cosmology · Physics 2017-03-08 Tommi Markkanen , Arttu Rajantie

The method of images is used to calculate the Casimir energy in Euclidean space with Dirichlet boundary conditions for two planar models, namely: i. the non-relativistic Landau problem for a charged particle of mass m for which -…

High Energy Physics - Theory · Physics 2015-05-13 S. G. Kamath

We compute the vacuum polarization for a massless, conformally coupled scalar field on the covering space of global, four-dimensional, anti-de Sitter space-time. Since anti-de Sitter space is not globally hyperbolic, boundary conditions…

General Relativity and Quantum Cosmology · Physics 2020-10-13 Thomas Morley , Peter Taylor , Elizabeth Winstanley

We study the static and spherically symmetric exact solution of the Einstein-massless scalar equations given by Janis, Newman and Winicour. We find that this solution satisfies the weak energy condition and has strong globally naked…

General Relativity and Quantum Cosmology · Physics 2009-10-28 K. S. Virbhadra , S. Jhingan , P. S. Joshi

We consider an ideal gas of active Brownian particles that undergo self-propelled motion and both translational and rotational diffusion under the influence of gravity. We solve analytically the corresponding Smoluchowski equation in two…

Soft Condensed Matter · Physics 2018-03-02 Sophie Hermann , Matthias Schmidt

A realistic interpretation of Schroedinger and Dirac equations for density matrices is proposed, in which the difference between the position arguments of the density matrix is considered as an objective extra space dimension. "Particle"…

Quantum Physics · Physics 2007-05-23 A. Raiteri

In the work's considered density of vacuum energy and dynamic of scalar field in multidimensional theory with cosmological constant. Using method of N.N.Bogolubov coefficients, was gotten expression for influence of anisotropic metric to…

General Physics · Physics 2012-03-05 Sergey Yakovlev

We study the vacuum polarization (Casimir) energy in renormalizable, continuum quantum field theory in the presence of a background field, designed to impose Dirichlet boundary conditions on the fluctuating quantum field. In two and three…

High Energy Physics - Theory · Physics 2007-05-23 H. Weigel

The imposition of boundary conditions upon a quantized field can lead to singular energy densities on the boundary. We treat the boundaries as quantum mechanical objects with a nonzero position uncertainty, and show that the singular energy…

Quantum Physics · Physics 2009-10-31 L. H. Ford , N. F. Svaiter

In this paper we study a new symmetry argument that results in a vacuum state with strictly vanishing vacuum energy. This argument exploits the well-known feature that de Sitter and Anti- de Sitter space are related by analytic…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Gerard 't Hooft , Stefan Nobbenhuis

In this paper, we consider the problem of nonlinear (in particular, saturated) stabilization of the high-dimensional wave equation with Dirichlet boundary conditions. The wave dynamics are subject to a dissipative nonlinear velocity…

Analysis of PDEs · Mathematics 2022-08-30 Nicolas Vanspranghe , Francesco Ferrante , Christophe Prieur

The Casimir effect for general Robin conditions on the surface of a cylinder in $D$-spacetime dimensions is studied for massive scalar field with general curvature coupling. The energy distribution and vacuum stress are investigated. We…

High Energy Physics - Theory · Physics 2009-11-07 August Romeo , Aram A. Saharian

We give a general method to find exact cosmological solutions for scalar-field dark energy in the presence of perfect fluids. We use the existence of invariant transformations for the Wheeler De Witt (WdW) equation. We show that the…

General Relativity and Quantum Cosmology · Physics 2015-10-02 Andronikos Paliathanasis , Michael Tsamparlis , Spyros Basilakos , John D. Barrow

In this paper, we consider the Cauchy problem for pressureless gases in two space dimensions with generic smooth initial data (density and velocity). These equations give rise to singular curves, where the mass has positive density…

Analysis of PDEs · Mathematics 2023-07-24 Alberto Bressan , Geng Chen , Shoujun Huang

A nonstatic and circularly symmetric exact solution of the Einstein equations (with a cosmological constant $\Lambda$ and null fluid) in $2+1$ dimensions is given. This is a nonstatic generalization of the uncharged spinless BTZ metric. For…

General Relativity and Quantum Cosmology · Physics 2009-10-22 K. S. Virbhadra

The problem of longitudinal oscillations of an electric field and a charge polarization density in QED vacuum is considered. Within the framework of semiclassical analysis, we calculate time-periodic solutions of bosonized (1+1)-dimensional…

Classical Physics · Physics 2016-09-08 E. Yu. Petrov , A. V. Kudrin

In the present paper, we investigate the ground state energy of a massless scalar field and generation of topological mass by considering a quasi-periodically identified Minkowski spacetime and the `half-Einstein Universe', that is, an…

High Energy Physics - Theory · Physics 2021-07-06 Paulo J. Porfírio , Herondy F. Santana Mota , Gabriel Queiroz Garcia