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Beginning from the semiclassical Hamiltonian, the Fermi pressure and Bohm potential for the quantum hydrodynamics application (QHD) at finite temperature are consistently derived in the framework of the local density approximation with the…

Plasma Physics · Physics 2018-04-18 Zh. A. Moldabekov , M. Bonitz , T. S. Ramazanov

The quantum dynamics of a low-dimensional system in contact with a large but finite harmonic bath is theoretically investigated by coarse-graining the bath into a reduced set of effective energy states. In this model, the couplings between…

Chemical Physics · Physics 2024-01-29 Loïse Attal , Cyril Falvo , Florent Calvo , Pascal Parneix

Quantum Gibbs state sampling algorithms generally suffer from either scaling exponentially with system size or requiring specific knowledge of spectral properties \textit{a priori}. Also, these algorithms require a large overhead of bath or…

Quantum Physics · Physics 2020-09-02 Jeffrey Cohn , Khadijeh Sona Najafi , Forest Yang , Barbara Jones , James K. Freericks

When a parameter quench is performed in an isolated quantum system with a complete set of constants of motion, its out of equilibrium dynamics is considered to be well captured by the Generalized Gibbs Ensemble (GGE), characterized by a set…

Mesoscale and Nanoscale Physics · Physics 2021-02-23 Lorenzo Rossi , Fabrizio Dolcini , Fabio Cavaliere , Niccolò Traverso Ziani , Maura Sassetti , Fausto Rossi

We present quantum algorithms for solving two problems regarding stochastic processes. The first algorithm prepares the thermal Gibbs state of a quantum system and runs in time almost linear in $\sqrt{N \beta/{\cal Z}}$ and polynomial in…

Quantum Physics · Physics 2017-01-11 Anirban Narayan Chowdhury , Rolando D. Somma

We consider the non-equilibrium dynamics in isolated systems, described by quantum field theories (QFTs). After being prepared in a density matrix that is not an eigenstate of the Hamiltonian, such systems are expected to relax locally to a…

Quantum Gases · Physics 2015-06-02 F. H. L. Essler , G. Mussardo , M. Panfil

Within the framework of relativistic quantum field theory, a novel method is established which allows to distinguish non-equilibrium states admitting locally a thermodynamic interpretation. The basic idea is to compare these states with…

High Energy Physics - Phenomenology · Physics 2015-06-25 Detlev Buchholz , Izumi Ojima , Hansjoerg Roos

We reconsider the non-equilibrium dynamics of closed quantum systems. In particular we focus on the thermalization of integrable systems. Here we show how the generalized Gibbs Ensemble (GGE) can be constructed as the best approximation to…

Quantum Physics · Physics 2017-05-11 Dries Sels , Michiel Wouters

We present a quantum algorithm to prepare the thermal Gibbs state of interacting quantum systems. This algorithm sets a universal upper bound D^alpha on the thermalization time of a quantum system, where D is the system's Hilbert space…

Quantum Physics · Physics 2013-05-29 David Poulin , Pawel Wocjan

The force estimation problem in quantum metrology with an arbitrary non-Markovian Gaussian bath is considered. No assumptions are made on the bath spectrum and coupling strength with the probe. Considering the natural global unitary…

Quantum Physics · Physics 2016-12-22 Camille Lombard Latune , Ilya Sinayskiy , Francesco Petruccione

We calculate the nonequilibrium mean-field 'temperature' of a Brownian system in contact with a heat bath. We consider two different cases: an equilibrium bath in the presence of strong external forces and a nonequilibrium bath. By proving…

Statistical Mechanics · Physics 2011-06-30 I Santamaría-Holek , A. Pérez-Madrid

Quantum entanglement is considered, by and large, to be a very delicate and non-robust phenomenon that is very hard to maintain in the presence of noise, or non-zero temperatures. In recent years however, and motivated, in part, by a quest…

Quantum Physics · Physics 2017-02-27 Lior Eldar

We present a detailed study of the quantum dissipative dynamics of a charged particle in a magnetic field. Our focus of attention is the effect of dissipation on the low- and high-temperature behavior of the specific heat at constant…

Statistical Mechanics · Physics 2015-05-14 S. Dattagupta , Jishad Kumar , S. Sinha , P. A. Sreeram

In this paper we study the thermal equilibration of small bipartite Bose-Hubbard systems, both quantum mechanically and in mean-field approximation. In particular we consider small systems composed of a single-mode "thermometer" coupled to…

Quantum Physics · Physics 2019-06-26 Ralf Bürkle , James R. Anglin

A theory of local temperature measurement of an interacting quantum electron system far from equilibrium via a floating thermoelectric probe is developed. It is shown that the local temperature so defined is consistent with the zeroth,…

Mesoscale and Nanoscale Physics · Physics 2016-06-08 Charles A. Stafford

The principle of microscopic reversibility lies at the core of fluctuation theorems, which have extended our understanding of the second law of thermodynamics to the statistical level. In the quantum regime, however, this elementary…

We consider two related tasks: (a) estimating a parameterisation of a given Gibbs state and expectation values of Lipschitz observables on this state; and (b) learning the expectation values of local observables within a thermal or quantum…

Quantum Physics · Physics 2024-09-09 Emilio Onorati , Cambyse Rouzé , Daniel Stilck França , James D. Watson

The Eigenstate Thermalization Hypothesis implies that for a thermodynamically large system in one of its eigenstates, the reduced density matrix describing any finite subsystem is determined solely by a set of {\it relevant} conserved…

Statistical Mechanics · Physics 2017-01-04 Sourav Nandy , Arnab Sen , Arnab Das , Abhishek Dhar

In many quantum quench experiments involving cold atom systems the post-quench system can be described by a quantum field theory of free scalars or fermions, typically in a box or in an external potential. We work with free scalars in…

High Energy Physics - Theory · Physics 2023-08-29 Parijat Banerjee , Adwait Gaikwad , Anurag Kaushal , Gautam Mandal

Calculating the properties of Gibbs states is an important task in Quantum Chemistry and Quantum Machine Learning. Previous work has proposed a quantum algorithm which predicts Gibbs state expectation values for $M$ observables from only…

Quantum Physics · Physics 2024-09-10 Arnav Sharma , Kevin Obenland