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A small quantum scattering system (the microsystem) is studied in interaction with a large quantum system (the macrosystem) described by unknown stochastic variables. The interaction between the two systems is diagonal for the microsystem…

Quantum Physics · Physics 2007-05-23 Karl-Erik Eriksson

We demonstrate that the Einstein relation for the diffusion of a particle in the random energy landscape with the Gaussian density of states is an exclusive 1D property and does not hold in higher dimensions. We also consider the analytical…

Disordered Systems and Neural Networks · Physics 2020-02-21 S. V. Novikov

We consider that no mean magnetic field exists during this epoch, but that there is a mean magnetic energy associated with large-scale magnetic inhomogeneities. We study the evolution of these inhomogeneities and their influence on the…

Astrophysics · Physics 2009-01-14 E. Battaner , E. Florido , J. Jimenez-Vicente

Semiclassical Einstein-Langevin equations for arbitrary small metric perturbations conformally coupled to a massless quantum scalar field in a spatially flat cosmological background are derived. Use is made of the fact that for this problem…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Antonio Campos , Enric Verdaguer

An action principle of singular hypersurfaces in general relativity and scalar-tensor type theories of gravity in the Einstein frame is presented without assuming any symmetry. The action principle is manifestly doubly covariant in the…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Shinji Mukohyama

The `missing baryons' of the near universe are believed to be principally in a partially ionized state. Although passing electromagnetic waves are dispersed by the plasma, the effect has hitherto not been utilized as a means of detection…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Richard Lieu , Lingze Duan , T. W. B. Kibble

Averaging in general relativity is a complicated operation, due to the general covariance of the theory and the non-linearity of Einstein's equations. The latter of these ensures that smoothing spacetime over cosmological scales does not…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Chris Clarkson , Timothy Clifton , Alan Coley , Rockhee Sung

Gravitational waves offer a potent mean to test the underlying theory of gravity. In general theories of gravity, such as scalar-tensor theories, one expects modifications in the friction term and the sound speed in the gravitational wave…

General Relativity and Quantum Cosmology · Physics 2024-10-17 Yi-Fu Cai , Guillem Domènech , Alexander Ganz , Jie Jiang , Chunshan Lin , Bo Wang

I apply the scattering approach within the framework of macroscopic quantum electrodynamics to derive the variances and mean values of the energy density and intensity for a system of an arbitrary object in an arbitrary environment. To…

Mesoscale and Nanoscale Physics · Physics 2023-12-15 Florian Herz

When the semi-positive cosmological constant is dynamical, the naive Euclidean Einstein action is unbounded from below and the Hartle-Hawking wavefunction of the universe is not normalizable. With the inclusion of back-reaction (a crucial…

High Energy Physics - Theory · Physics 2007-05-23 Saswat Sarangi , S. -H. Henry Tye

In general, Maxwell's equations require that a wave of electric field be accompanied by a wave of magnetic field, and vice versa. However, it is possible to have a plane wave in a dielectric medium with electric field E parallel to the wave…

Plasma Physics · Physics 2007-05-23 Kirk T. McDonald

Macroscopic quantum electrodynamics (MQED) provides a unified framework to describe quantum electromagnetic fields in the presence of arbitrary macroscopic environments. Central to this theory is the field correlation, which governs both…

Quantum Physics · Physics 2026-03-02 Daigo Oue

Quantum electrodynamics under conditions of distinguishability of interacting matter entities, and of controlled actions and back-actions between them, is considered. Such "mesoscopic quantum electrodynamics" is shown to share its dynamical…

Quantum Physics · Physics 2015-09-30 L. I. Plimak , Misha Ivanov , A. Aiello , S. Stenholm

In a previous paper [gr-qc/0104001; Class. Quant. Grav. 18 (2001) 3595-3610] we have shown that the occurrence of curved spacetime ``effective Lorentzian geometries'' is a generic result of linearizing an arbitrary classical field theory…

General Relativity and Quantum Cosmology · Physics 2009-11-07 C. Barcelo , S. Liberati , Matt Visser

We introduce a simple and straight-forward averaging procedure, which is a generalization of one which is commonly used in electrodynamics, and show that it possesses all the characteristics we require for linearized averaging in general…

General Relativity and Quantum Cosmology · Physics 2008-11-26 William R. Stoeger , Amina Helmi , Diego F. Torres

Based on the Generalized Principle of Inertia, which states that: \emph{An inanimate object moves freely, that is, with zero acceleration, in its own spacetime, whose geometry is determined by all of the forces affecting it,} we geometrize…

General Physics · Physics 2020-01-08 Yaakov Friedman , Tzvi Scarr

This revision includes clarified exposition and simplified analysis. Solutions of the Einstein equations which are periodic and have standing gravitational waves are valuable approximations to more physically realistic solutions with…

General Relativity and Quantum Cosmology · Physics 2010-05-12 Steven Detweiler

The article proposes an amendment to the relativistic continuum mechanics which introduces the relationship between density tensors and the curvature of spacetime. The resulting formulation of a symmetric stress-energy tensor for a system…

General Physics · Physics 2023-12-19 Piotr Ogonowski

At lower energies, the resonances in scattering experiments are often isolated. In quantum chaotic many-body, disordered or generically stochastic systems, the resonances overlap at larger energies. Eventually, the Ericson regime is reached…

Statistical Mechanics · Physics 2026-03-13 Simon Köhnes , Jiongning Che , Barbara Dietz , Thomas Guhr

Einstein-Cartan theory is an extension of the standard formulation of General Relativity where torsion (the antisymmetric part of the affine connection) is non-vanishing. Just as the space-time metric is sourced by the stress-energy tensor…

General Relativity and Quantum Cosmology · Physics 2019-12-30 Francisco Cabral , Francisco S. N. Lobo , Diego Rubiera-Garcia