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The dynamical behavior for a quantum Brownian particle is investigated under a random potential of the fractional iterative map on a one-dimensional lattice. For our case, the quantum expectation values can be obtained numerically from the…

Statistical Mechanics · Physics 2007-05-23 Kyungsik Kim , Y. S. Kong , M. K. Yum , J. T. Kim

We investigate the previously unexplored quantum dynamics of non-relativistic, spinless particles propagating in curved spaces with torsion. Our findings demonstrate that while torsion has been predominantly associated with spin, it can…

General Relativity and Quantum Cosmology · Physics 2025-11-19 Tomoi Koide , Armin van de Venn

In the present work we present the full treatment of scalar and vector cosmological perturbations in a non-singular bouncing universe in the context of metric $f(R)$ cosmology. Scalar metric perturbations in $f(R)$ cosmology were previously…

General Relativity and Quantum Cosmology · Physics 2019-11-20 Pritha Bari , Kaushik Bhattacharya

We investigate quantum vacuum effects for a massive scalar field, induced by two planar boundaries in background of a linearly expanding spatially flat Friedmann-Robertson-Walker spacetime for an arbitrary number of spatial dimensions. For…

High Energy Physics - Theory · Physics 2020-02-18 A. A. Saharian , T. A. Petrosyan , S. V. Abajyan , B. B. Nersisyan

The fundamental vacuum state of quantum fields, related to Minkowski space, produces divergent fluctuations that must be suppressed in order to bring reality to the description of physical systems. As a consequence, negative vacuum…

Quantum Physics · Physics 2021-06-14 G. H. S. Camargo , V. A. De Lorenci , A. L. Ferreira Junior , C. C. H. Ribeiro

In this work, I review some aspects concerning the evolution of quantum low-energy fields in a foamlike spacetime, with involved topology at the Planck scale but with a smooth metric structure at large length scales, as follows. Quantum…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Luis J. Garay

In spatially uniform, but time-dependent dielectric media with equal electric and magnetic response, classical electromagnetic waves propagate exactly like in empty, flat space with transformed time, called conformal time, and so do quantum…

Quantum Physics · Physics 2025-01-07 Ziv Landau , Ulf Leonhardt

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 establish that the exact quantum dynamics of a Brownian particle in the Caldeira-Leggett model can be mapped, at any temperature, onto a classical, non-Markovian stochastic process in phase space. Starting from a correlated thermal…

Quantum Physics · Physics 2025-12-11 Dmitriy Kondaurov , Evgeny Polyakov

We are studying the dynamics of a one-dimensional field in a non-commutative Euclidean space. The non-commutative space we consider is the one that emerges in the context of three dimensional Euclidean quantum gravity: it is a deformation…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Karim Noui

The quantum Brownian motion paradigm provides a unified framework where one can see the interconnection of some basic quantum statistical processes like decoherence, dissipation, particle creation, noise and fluctuation. We treat the case…

General Relativity and Quantum Cosmology · Physics 2008-11-26 B. L. Hu , Andrew Matacz

We study the implications of quantum fluctuations of a dispersive medium, under steady rotation, either in or out of thermal equilibrium with its environment. A rotating object exhibits a quantum instability by dissipating its mechanical…

Quantum Physics · Physics 2014-07-23 Mohammad F. Maghrebi , Robert L. Jaffe , Mehran Kardar

We study a noninteracting supersymmetric model in an expanding FRW spacetime. A soft supersymmetry breaking induces a nonzero contribution to the vacuum energy density. A short distance cutoff of the order of Planck length provides a scale…

High Energy Physics - Theory · Physics 2011-05-13 Neven Bilic

The quantization of the Friedmann-Robertson-Walker spacetime in the presence of a negative cosmological constant was used in a recent paper to conclude that there are solutions that avoid singularities (big bang--big crunch) at the quantum…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Paolo Amore , Alfredo Aranda , Mayra Cervantes , J. L. Díaz-Cruz , Francisco M. Fernández

We consider Brownian motions with one-sided collisions, meaning that each particle is reflected at its right neighbour. For a finite number of particles a Sch\"{u}tz-type formula is derived for the transition probability. We investigate an…

Mathematical Physics · Physics 2015-04-23 Patrik L. Ferrari , Herbert Spohn , Thomas Weiss

We compute the fully renormalized one-loop effective action for two interacting and self-interacting scalar fields in FRW space-time. We then derive and solve the quantum corrected equations of motion both for fields that dominate the…

General Relativity and Quantum Cosmology · Physics 2015-03-20 Tommi Markkanen , Anders Tranberg

We show how quantum fields can be used to measure the curvature of spacetime. In particular, we find that knowledge of the imprint that spacetime curvature leaves in the correlators of quantum fields suffices, in principle, to reconstruct…

General Relativity and Quantum Cosmology · Physics 2016-03-02 Mehdi Saravani , Siavash Aslanbeigi , Achim Kempf

Quantum effects are expected to modify the cosmological dynamics of the early universe while maintaining some (potentially discrete) notion of space-time structure. In one approach, loop quantum cosmology, current models are shown here to…

General Relativity and Quantum Cosmology · Physics 2026-04-29 Martin Bojowald , Manuel Diaz , Erick I. Duque

The linearized Einstein field equations with the renormalized stress tensor of a massless quantum scalar field as source are solved in the 4-dimensional spacetime near an infinite plane boundary. The motion of particles and light is…

High Energy Physics - Theory · Physics 2013-04-24 V. A. De Lorenci , L. G. Gomes , E. S. Moreira

We study the classical and quantum models of a scalar field Friedmann-Robertson-Walker (FRW) cosmology with an eye to the issue of time problem in quantum cosmology. We introduce a canonical transformation on the scalar field sector of the…

General Relativity and Quantum Cosmology · Physics 2015-06-11 Babak Vakili