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In classical thermodynamics the Euler relation is an expression for the internal energy as a sum of the products of canonical pairs of extensive and intensive variables. For quantum systems the situation is more intricate, since one has to…

Quantum Physics · Physics 2021-07-27 Akram Touil , Kevin Weber , Sebastian Deffner

A quasi-static process is realized in a purely quantum-mechanical model which is described by oscillator (or particle) systems having relative-phase interactions. Time development of a mixture of two oscillator (or particle) systems which…

Statistical Mechanics · Physics 2016-08-31 T. Kobayashi

The density operator for a quantum system in thermal equilibrium with its environment depends on Planck's constant, as well as the temperature. At high temperatures, the Weyl representation, that is, the thermal Wigner function, becomes…

Quantum Physics · Physics 2021-06-30 Alfredo M. Ozorio de Almeida , Gert-Ludwig Ingold , Olivier Brodier

Quantum collision models normally consist of a system interacting with a set of ancillary units representing the environment. While these ancillary systems are usually assumed to be either two level systems (TLS) or harmonic oscillators, in…

Quantum Physics · Physics 2024-05-31 Stefano Cusumano , Gabriele De Chiara

The thermal or equilibrium ensemble is one of the most ubiquitous states of matter. For models comprised of many locally interacting quantum particles, it describes a wide range of physical situations, relevant to condensed matter physics,…

Quantum Physics · Physics 2023-12-06 Álvaro M. Alhambra

The approximate representation of a quantum solid as an equivalent composite semi-classical solid is considered for insulating materials. The composite is comprised of point ions moving on a potential energy surface. In the classical bulk…

Materials Science · Physics 2007-05-23 Aditi Mallik , Keith Runge , James W. Dufty , Hai-Ping Cheng

The quantum properties of electromagnetic, mechanical or other harmonic oscillators can be revealed by investigating their strong coherent coupling to a single quantum two level system in an approach known as cavity quantum electrodynamics…

Thermodynamics of quasianti-Hermitian quaternionic systems with constant number of particles in equilibrium is studied. A toy model is introduced and the physically relevant quantities are derived. The energy fluctuation which shows that…

Quantum Physics · Physics 2013-08-02 S. A. Alavi

We describe a classical thermodynamic model that reproduces the main features of the solid hydrogen phase diagram. In particular, we show how the general structure types that are found by electronic structure calculations and the quantum…

Disordered Systems and Neural Networks · Physics 2017-04-05 Ioan B Magdău , Miriam Marques , Balint Borgulya , Graeme J Ackland

The theory of quantum thermodynamics investigates how the concepts of heat, work, and temperature can be carried over to the quantum realm, where fluctuations and randomness are fundamentally unavoidable. These lecture notes provide an…

Quantum Physics · Physics 2026-04-17 Patrick P. Potts

We formulate a canonical quantization of Equilibrium Thermodynamics by applying Dirac's theory of constrained systems. Thermodynamic variables are treated as conjugate pairs of coordinates and momenta, allowing extensive and intensive…

Quantum Physics · Physics 2025-11-19 Luis F. Santos , Victor Hugo M. Ramos , Danilo Cius , Mario C. Baldiotti , Bárbara Amaral

We describe a finite inhomogeneous three dimensional system of classical particles which interact through short and (or) long range interactions by means of a simple analytic spin model. The thermodynamic properties of the system are worked…

Nuclear Theory · Physics 2009-10-31 J. Richert , P. Wagner , M. Henkel , J. M. Carmona

We investigate the thermodynamics of integrable classical field theories under the effect of a random initial configuration, motivated by the nonequilibrium evolution of quantum field theories. The approach to thermal equilibrium is…

Statistical Mechanics · Physics 2016-10-05 P. E. G. Assis

Advances in controlling and measuring systems of ultra-cold atoms provided strong motivation to theoretical investigations of quantum dynamics in closed many-body systems. Fundamental questions on quantum dynamics and statistical mechanics…

Quantum Gases · Physics 2015-12-04 Ehud Altman

Quantum typicality refers to the phenomenon that the expectation values of any given observable are nearly identical for the overwhelming majority of all normalized vectors in a sufficiently high-dimensional Hilbert (sub-)space. As a…

Statistical Mechanics · Physics 2025-10-09 Peter Reimann , Nicolas Nessi

The application of a classical approach to various quantum problems - the secular perturbation approach to quantization of a hydrogen atom in external fields and a helium atom, the adiabatic switching method for calculation of a…

Quantum Physics · Physics 2015-05-18 Evgeni A. Solov'ev

We revisist the issue of entanglement of thermal equilibrium states in composite quantum systems. The possible scenarios are exemplified in bipartite qubit/qubit and qubit/qutrit systems.

Quantum Physics · Physics 2009-11-11 O. Osenda , G. A. Raggio

High temperature expansion of the partition function for a particle on a segment of a line is found to show an example of the quantum system that thermodynamical functions do not approach the thermodynamical functions of its classical…

Physics Education · Physics 2007-05-23 Michal Demetrian

The theory relevant to the study of matter in equilibrium with the radiation field is thermal quantum electrodynamics (TQED). We present a formulation of the theory, suitable for non relativistic fluids, based on a joint functional integral…

Quantum Physics · Physics 2009-11-13 Pascal R. Buenzli , Philippe A. Martin , Marc D. Ryser

Quantum thermodynamics aims to explore quantum features to enhance energy conversion beyond classical limits. While significant progress has been made, the understanding of caloric potentials in quantum systems remains incomplete. In this…

Quantum Physics · Physics 2025-02-27 Clebson Cruz , J. S. Amaral , Mario Reis