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In this paper we investigate the Quantum Brownian motion of a point particle induced by quantum vacuum fluctuations of a massless scalar field in (3 + 1)-dimensional Minkowski spacetime with distinct conditions (Dirichlet, Neumann, mixed…

High Energy Physics - Theory · Physics 2023-05-10 Éwerton J. B. Ferreira , Eliza M. B. Guedes , Herondy F. Santana Mota

Quantum fluctuations of the vacuum stress-energy tensor are highly non-Gaussian, and can have unexpectedly large effects on spacetime geometry. In this paper, we study a two-dimensional dilaton gravity model coupled to a conformal field, in…

General Relativity and Quantum Cosmology · Physics 2020-12-18 S. Carlip , Ricardo A. Mosna , J. P. M. Pitelli

We analyze the vacuum fluctuations and the stress-energy tensor of a scalar field of mass $M$ in a conical spacetime, where the topological singularity at the apex requires boundary conditions for the field equation. The necessity of…

High Energy Physics - Theory · Physics 2025-12-05 João Paulo M. Pitelli , Ricardo A. Mosna , Victor Hugo M. Ramos , João C. A. Barata

We develop a simple model to study classical fields on the background of a fluctuating spacetime volume. It is applied to formulate the stochastic Einstein equations with a perfect-fluid source. We investigate the particular case of a…

General Relativity and Quantum Cosmology · Physics 2017-09-06 Vladimir Dzhunushaliev , Hernando Quevedo

We study a supersymmetric model in curved background spacetime. We calculate the effective action and the vacuum expectation value of the energy momentum tensor using a covariant regularization procedure. A soft supersymmetry breaking…

High Energy Physics - Theory · Physics 2015-05-30 Neven Bilic , Silvije Domazet , Branko Guberina

Zero-point fluctuations in the background of a cosmic string provide an opportunity to study the effects of topology in quantum field theory. We use a scattering theory approach to compute quantum corrections to the energy density of a…

High Energy Physics - Theory · Physics 2025-05-26 M. Koike , X. Laquidain , N. Graham

Vacuum polarization of a massive scalar field in the background of a two-dimensional version of a spinning cosmic string is investigated. It is shown that when the `radius of the universe' is such that spacetime is globally hyperbolic the…

General Relativity and Quantum Cosmology · Physics 2012-08-27 V. A. De Lorenci , E. S. Moreira,

More than half of a century has passed since the free energy of classical fluids defined by second Legendre transform was derived as a functional of density-density correlation function. It is now becoming an increasingly significant issue…

Statistical Mechanics · Physics 2018-12-05 Hiroshi Frusawa

We propose a unified single-field description of the galactic Dark Matter and various uniform scalar fields for the inflation and cosmological constant. The two types of effects could originate from a fluid of both spatially and temporally…

Astrophysics · Physics 2016-05-25 Anaelle Halle , HongSheng Zhao , Baojiu Li

Simple models of a classical spacetime foam are considered, which consist of identical static defects embedded in Minkowski spacetime. Plane-wave solutions of the vacuum Maxwell equations with appropriate boundary conditions at the defect…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. Bernadotte , F. R. Klinkhamer

We generalise results of Ford and Roman which place lower bounds -- known as quantum inequalities -- on the renormalised energy density of a quantum field averaged against a choice of sampling function. Ford and Roman derived their results…

General Relativity and Quantum Cosmology · Physics 2008-11-26 C. J. Fewster , S. P. Eveson

We consider an electron-phonon system in two and three dimensions on square, hexagonal and cubic lattices. The model is a modification of the standard Holstein model where the optical branch is appropriately curved in order to have a…

Statistical Mechanics · Physics 2009-10-31 N. Macris , C. -A. Piguet

In this paper we analyze the vacuum expectation values of the field squared and the energy-momentum tensor associated to a massive scalar field in a higher dimensional cosmic string spacetime, obeying Dirichlet or Neumann boundary…

High Energy Physics - Theory · Physics 2011-07-07 E. R. Bezerra de Mello , A. A. Saharian

We reexamine how quantum density fluctuations in condensates of ultra-cold fermi gases lead to fluctuations in phonon times-of-flight, an effect that increases as density is reduced. We suggest that these effects should be measurable in…

Quantum Gases · Physics 2020-05-12 Da-Shin Lee , Chi-Yong Lin , Ray J. Rivers

We argue that quantum-gravitational fluctuations in the space-time background give the vacuum non-trivial optical properties that include diffusion and consequent uncertainties in the arrival times of photons, causing stochastic…

General Relativity and Quantum Cosmology · Physics 2009-09-11 John Ellis , N. E. Mavromatos , D. V. Nanopoulos

We investigate the vacuum-induced current density for a charged scalar field in a $(D+1)$-dimensional cosmic dispiration spacetime threaded by a magnetic flux. This background combines a cosmic string and a screw dislocation, yielding a…

High Energy Physics - Theory · Physics 2026-04-10 Herondy Mota

Universal properties of entangled many-body states are controlled by their symmetry and quantum fluctuations. By magnetic-field tuning of the spin-orbital degeneracy in a Kondo-correlated quantum dot, we have modified quantum fluctuations…

In this paper we analyze the vacuum expectation values of the field squared and the energy-momentum tensor associated to a massive scalar field in a higher dimensional cosmic string spacetime, obeying Dirichlet or Neumann boundary…

High Energy Physics - Theory · Physics 2011-11-18 Eugênio R. Bezerra de Mello , Aram A. Saharian

From calculations of the variance of fluctuations and of the mean of the energy density of a massless scalar field in the Minkowski vacuum as a function of an intrinsic scale defined by the world function between two nearby points (as used…

General Relativity and Quantum Cosmology · Physics 2014-11-17 B. L. Hu , Nicholas. G. Phillips

We present a study of energy density and pressure of a free real scalar quantum field after its decoupling from a thermal bath in the spatially flat Friedman-Lema\^itre-Robertson-Walker space-time by solving the Klein-Gordon equation both…

General Relativity and Quantum Cosmology · Physics 2025-04-15 F. Becattini , D. Roselli