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I present an explicit classical simulation of arbitrary quantum noise for quantum models in which one qubit interacts with a quantum bath. The classical model simulates the interaction of the bath and the qubit by random unitary evolutions.…

Quantum Physics · Physics 2017-11-01 Seyyed M. H. Halataei

We set the formalism to study the way in which the choice of canonical equilibrium initial conditions affect the real-time dynamics of quantum disordered models. We use a path integral formulation on a time contour with real and imaginary…

Disordered Systems and Neural Networks · Physics 2019-05-22 Leticia F. Cugliandolo , Gustavo S. Lozano , Nicolas Nessi

The extreme electromagnetic or gravitational fields associated with some astrophysical objects can give rise to macroscopic effects arising from the physics of the quantum vacuum. Therefore, these objects are incredible laboratories for…

High Energy Astrophysical Phenomena · Physics 2012-09-21 Dan Mazur

Current fluctuations in a dissipative two-state system have been studied using a novel quantum dynamics simulation method. After a transformation of the path integrals, the tunneling dynamics is computed by deterministic integration over…

Statistical Mechanics · Physics 2009-10-31 J. Stockburger , C. H. Mak

In the framework of Inflationary theory, the assumption that the quantum state of the perturbations is a non-vacuum state leads to a difficulty: non-vacuum initial states imply, in general, a large energy density of inflaton field quanta,…

Astrophysics · Physics 2007-05-23 Alejandro Gangui , Jerome Martin , Mairi Sakellariadou

When two or more objects move relative to one another in vacuum, they experience a drag force which, at zero temperature, usually goes under the name of quantum friction. This contactless non-conservative interaction is mediated by the…

Quantum Physics · Physics 2022-04-01 Daniel Reiche , Francesco Intravaia , Kurt Busch

We discuss the challenges of motivating, constructing, and quantizing a canonically normalized inflationary perturbation in spatially curved universes. We show that this has historically proved challenging due to the interaction of…

General Relativity and Quantum Cosmology · Physics 2024-07-10 Mary I. Letey , Zakhar Shumaylov , Fruzsina J. Agocs , Will J. Handley , Michael P. Hobson , Anthony N. Lasenby

We establish an analytical criterion for dynamical thermalization within harmonic systems, applicable to both classical and quantum models. Specifically, we prove that thermalization of various observables, such as particle energies in…

Statistical Mechanics · Physics 2025-07-29 Marco Cattaneo , Marco Baldovin , Dario Lucente , Paolo Muratore-Ginanneschi , Angelo Vulpiani

In classical mechanics, a natural way to simplify a many-body problem is to ``replace'' some of the elements of the composite system with surrogate \textit{force fields}. In the realm of quantum mechanics, however, such a description is…

Quantum Physics · Physics 2021-08-06 Piotr Szańkowski

Controlled quantum mechanical devices provide a means of simulating more complex quantum systems exponentially faster than classical computers. Such "quantum simulators" rely heavily upon being able to prepare the ground state of…

Quantum Physics · Physics 2012-08-01 Dvir Kafri , Jacob M. Taylor

In this paper a formalism for studying the dynamics of quantum systems coupled to classical spin environments is reviewed. The theory is based on generalized antisymmetric brackets and naturally predicts open-path off-diagonal geometric…

Quantum Physics · Physics 2016-10-21 Alessandro Sergi

Calculations of nonequilibrium processes become increasingly feasable in quantum field theory from first principles. There has been important progress in our analytical understanding based on 2PI generating functionals. In addition, for the…

High Energy Physics - Theory · Physics 2010-02-04 J. Berges , Sz. Borsanyi

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

Free quantum field theories on curved backgrounds are discussed via three explicit examples: the real scalar field, the Dirac field and the Proca field. The first step consists of outlining the main properties of globally hyperbolic…

Mathematical Physics · Physics 2015-05-19 Marco Benini , Claudio Dappiaggi

During the inflationary phase of the early universe, quantum fluctuations in the vacuum generate particles as they stretch beyond the Hubble length. These fluctuations are thought to result in the density fluctuations and gravitational…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Jeremy S. Heyl

It is shown that the vacuum state of weakly interacting quantum field theories can be described, in the Heisenberg picture, as a linear combination of randomly distributed incoherent paths that obey classical equations of motion with…

High Energy Physics - Theory · Physics 2009-11-07 Ram Brustein , David H. Oaknin

Phase transitions which occur at zero temperature when some non-thermal parameter like pressure, chemical composition or magnetic field is changed are called quantum phase transitions. They are caused by quantum fluctuations which are a…

Statistical Mechanics · Physics 2007-05-23 Thomas Vojta

We investigate the importance of including quantized initial conditions in Langevin dynamics for adsorbates interacting with a thermal reservoir of electrons. For quadratic potentials the time evolution is exactly described by a classical…

Materials Science · Physics 2010-07-23 Thomas Olsen , Jakob Schiøtz

We introduce a new picture of vacuum decay which, in contrast to existing semiclassical techniques, provides a real-time description and does not rely on classically-forbidden tunneling paths. Using lattice simulations, we observe vacuum…

High Energy Physics - Theory · Physics 2019-07-24 Jonathan Braden , Matthew C. Johnson , Hiranya V. Peiris , Andrew Pontzen , Silke Weinfurtner

We treat the effects of quantum field fluctuations on the decay of a meta-stable state of a self-coupled scalar field. We consider two varieties of field fluctuations and their potential effects in a semiclassical description. The first are…

High Energy Physics - Theory · Physics 2022-05-03 Haiyun Huang , L. H. Ford