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A consistent description of interactions between classical and quantum systems is relevant to quantum measurement theory, and to calculations in quantum chemistry and quantum gravity. A solution is offered here to this longstanding problem,…

Quantum Physics · Physics 2009-11-11 Michael J. W. Hall , Marcel Reginatto

The response of an arbitrary closed quantum system to a partially coherent electric field is investigated, with a focus on the transient coherences in the system. As a model we examine, both perturbatively and numerically, the coherences…

Quantum Physics · Physics 2014-03-05 Z. S. Sadeq , Paul Brumer

We study different notions of quantum correlations in multipartite systems of distinguishable and indistinguishable particles. Based on the definition of quantum coherence for a single particle, we consider two possible extensions of this…

Quantum Physics · Physics 2017-09-27 Jan Sperling , Armando Perez-Leija , Kurt Busch , Ian A. Walmsley

In this article we introduce a quasiprobability distribution of work that is based on the Wigner function. This construction rests on the idea that the work done on an isolated system can be coherently measured by coupling the system to a…

Quantum Physics · Physics 2023-11-03 Federico Cerisola , Franco Mayo , Augusto J. Roncaglia

Variational solutions of the Boltzmann equation usually rely on the concept of linear response. We extend the variational approach for tight-binding models at high entropies to a regime far beyond linear response. We analyze both weakly…

Quantum Gases · Physics 2015-06-22 Stephan Mandt

Following the formalism of Gell-Mann and Hartle, phenomenological equations of motion are derived from the decoherence functional formalism of quantum mechanics, using a path-integral description. This is done explicitly for the case of a…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Todd A. Brun

The emergence of macroscopic coherence in a many-body quantum system is a ubiquitous phenomenon across different physical systems and scales. This Chapter reviews key concepts characterizing such systems (correlation functions,…

Quantum Gases · Physics 2025-06-17 Nick P. Proukakis

Linearizing the appropriate kinetic equation we derive general response functions including selfconsistent mean fields or density functionals and collisional dissipative contributions. The latter ones are considered in relaxation time…

Nuclear Theory · Physics 2008-12-18 Klaus Morawetz , Uwe Fuhrmann

We extend the Keldysh technique to enable the computation of out-of-time order correlators. We show that the behavior of these correlators is described by equations that display initially an exponential instability which is followed by a…

Statistical Mechanics · Physics 2016-12-21 Igor L. Aleiner , Lara Faoro , Lev B. Ioffe

How quantum coherence influences thermodynamic behavior remains an open question in quantum thermodynamics. Here we investigate this relation within the pure dephasing framework, where a central qubit interacts with a finite Ising-like spin…

Quantum Physics · Physics 2026-03-31 Marino P. Lenzarini , Diogo O. Soares-Pinto

We analyze quantum coherence generated by non-interacting magnons in a ferromagnetic spin chain described by the isotropic Heisenberg model. The exact expression derived for the reduced density operator of an arbitrary subsystem reveals…

Quantum Physics · Physics 2025-09-23 V. C. Vieira , F. M. de Paula

Understanding how coherence of quantum systems affects thermodynamic quantities, such as work and heat, is essential for harnessing quantumness effectively in thermal quantum technologies. Here, we study the unique contributions of quantum…

Quantum Physics · Physics 2025-02-07 Rui Huang , Q. Y. Cai , Farzam Nosrati , Rosario Lo Franco , Zhong-Xiao Man

We construct a family of semimartingales that describes the behavior of a particle system with sticky-reflecting interaction. The model is a physical improvement of the Howitt-Warren flow, an infinite system of diffusion particles on the…

Probability · Mathematics 2022-05-02 Vitalii Konarovskyi

We introduce a new method for representing the low energy subspace of a bosonic field theory on the qubit space of digital quantum computers. This discretization leads to an exponentially precise description of the subspace of the…

Quantum Physics · Physics 2018-10-17 Alexandru Macridin , Panagiotis Spentzouris , James Amundson , Roni Harnik

We study the decoherence of a system of $N$ non-interacting heavy particles (atoms) due to coherent scattering with a background gas. We introduce a framework for computing the induced phase shift and loss of contrast for arbitrary…

Quantum Physics · Physics 2024-09-11 Leonardo Badurina , Clara Murgui , Ryan Plestid

Based on the constituent quasiparticle model of quark-gluon plasma (QGP), the matrix elements of the density operator and the Wigner function in the color phase space are presented in form of color path integrals over Wiener and SU(3) group…

Nuclear Theory · Physics 2020-02-12 V. Filinov , A. Larkin , V. Fortov

Investigating the behavior of noninteracting fermions subjected to local dephasing, we reveal that quasi-particle dephasing can induce superdiffusive transport. This superdiffusion arises from nodal points within the momentum distribution…

Statistical Mechanics · Physics 2023-12-18 Yu-Peng Wang , Chen Fang , Jie Ren

A theory recently proposed by the author aims to explain decoherence and the thermodynamical behaviour of closed systems within a conservative, unitary, framework for quantum gravity by assuming that the operators tied to the gravitational…

High Energy Physics - Theory · Physics 2010-04-06 Bernard S. Kay

We discuss decoherence in discrete-time quantum walks in terms of a phenomenological model that distinguishes spin and spatial decoherence. We identify the dominating mechanisms that affect quantum walk experiments realized with neutral…

Quantum Physics · Physics 2014-12-30 Andrea Alberti , Wolfgang Alt , Reinhard Werner , Dieter Meschede

It is commonly expected that quantum theory is universal, in that it describes the world at all scales. Yet, quantum effects at the macroscopic scale continue to elude our experimental observation. This fact is commonly attributed to…