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Descriptions of classical mechanics in Hilbert space go back to the work of Koopman and von Neumann in the 1930s. Decades later, van Hove derived a unitary representation of the group of contact transformations which recently has been used…

Quantum Physics · Physics 2025-04-02 Marcel Reginatto , Andrés Darío Bermúdez Manjarres , Sebastian Ulbricht

In this paper, we investigate the connection between Classical and Quantum Mechanics by dividing Quantum Theory in two parts: - General Quantum Axiomatics (a system is described by a state in a Hilbert space, observables are self-adjoint…

Quantum Physics · Physics 2009-11-07 H. Bergeron

The new method of multivariate data analysis based on the complements of classical probability distribution to quantum state and Schmidt decomposition is presented. We considered Schmidt formalism application to problems of statistical…

Quantum Physics · Physics 2017-01-10 Yu. I. Bogdanov , N. A. Bogdanova , D. V. Fastovets , V. F. Luckichev

Based on the concept of ensemble, it is proved in the manuscript that the probability amplitude function can also been used to describe the classical statistical system. The motion equations of probability amplitude functions of classical…

Classical Physics · Physics 2007-05-23 Xiaochun Mei

We present and discuss a formal approach for describing the quantum to classical crossover based on the group-theoretic construction of generalized coherent states. The method was originally introduced by L. Yaffe in 1982 for tackling…

Quantum Physics · Physics 2021-04-12 Alessandro Coppo , Alessandro Cuccoli , Caterina Foti , Paola Verrucchi

We study the statistical mechanics of classical and quantum systems in non-equilibrium steady states. Emphasis is placed on systems in strong thermal gradients. Various measures and functional forms of observables are presented. The quantum…

Chaotic Dynamics · Physics 2007-05-23 Dimitri Kusnezov , Eric Lutz , Kenichiro Aoki

An emissivity formula is derived using the generalised Fermi-Weizacker-Williams method of virtual photons which accounts for the recoil the charged particle experiences as it emits radiation. It is found that through this derivation the…

Plasma Physics · Physics 2015-12-09 J. L. Martins , M. Vranic , T. Grismayer , J. Vieira , R. A. Fonseca , L. O. Silva

The mechanism of the transition of a dynamical system from quantum to classical mechanics is one of the remaining challenges of quantum theory. Currently, it is considered to occur via decoherence caused by entanglement and/or stochastic…

Quantum Physics · Physics 2015-06-16 John S. Briggs , James M. Feagin

The dynamical equation of quantum mechanics are rewritten in form of dynamical equations for the measurable, positive marginal distribution of the shifted, rotated and squeezed quadrature introduced in the so called "symplectic tomography".…

Quantum Physics · Physics 2009-10-30 Stefano Mancini , Vladimir I. Man'ko , Paolo Tombesi

Focusing on isolated macroscopic systems, described either in terms of a quantum mechanical or a classical model, our two key questions are: In how far does an initial ensemble (usually far from equilibrium and largely unknown in detail)…

Statistical Mechanics · Physics 2013-11-13 Peter Reimann , Mykhaylo Evstigneev

We elucidate the basic physical mechanisms responsible for the quantum-classical transition in one-dimensional, bounded chaotic systems subject to unconditioned environmental interactions. We show that such a transition occurs due to the…

Quantum Physics · Physics 2007-10-18 Benjamin D. Greenbaum , Salman Habib , Kosuke Shizume , Bala Sundaram

We explore a possible link between the structure of space at short length scales and the emergence of classical phenomena at macroscopic scales. To this end we adopt the paradigm of non-commutative space at short length scales and…

Quantum Physics · Physics 2022-08-15 IB Pittaway , FG Scholtz

We present an alternative formalism of quantum mechanics tailored to statistical ensemble in phase space. The purpose of our work is to show that it is possible to establish an alternative autonomous formalism of quantum mechanics in phase…

Quantum Physics · Physics 2018-11-20 Chol Jong , Byong-Il Ri , Song-Guk Kim , Son-Il Jo , Shin-Hyok Jon , Namchol Choe

Recent years have seen a flurry of research activity in the study of minimal and autonomous information ratchets. However, the existing classical and quantum models are somewhat hard to compare, and, hence, quantifying possible quantum…

Statistical Mechanics · Physics 2019-04-24 Josey Stevens , Sebastian Deffner

Using a group theoretical approach we derive an equation of motion for a mixed quantum-classical system. The quantum-classical bracket entering the equation preserves the Lie algebra structure of quantum and classical mechanics: The bracket…

Quantum Physics · Physics 2009-10-30 Oleg V. Prezhdo , Vladimir V. Kisil

We sketch a group-theoretical framework, based on the Heisenberg-Weyl group, encompassing both quantum and classical statistical descriptions of mechanical systems. We re-define in group-theoretical terms the kinematical arena and the…

Quantum Physics · Physics 2009-11-13 J. K. Korbicz , M. Lewenstein

Time-symmetric quantum mechanics can be described in the usual Weyl--Wigner--Moyal formalism (WWM) by using the properties of the Wigner distribution, and its generalization, the cross-Wigner distribution. The use of the latter makes clear…

Quantum Physics · Physics 2015-10-12 Charlyne de Gosson , Maurice de Gosson

Efficiently simulating quantum circuits on classical computers is a fundamental challenge in quantum computing. This paper presents a novel theoretical approach that achieves substantial speedups over existing simulators for a wide class of…

Quantum Physics · Physics 2026-02-10 Daksh Shami

The original intent of the Koopman-von Neumann formalism was to put classical and quantum mechanics on the same footing by introducing an operator formalism into classical mechanics. Here we pursue their path the opposite way and examine…

Quantum Physics · Physics 2023-03-08 Igor Mezic

An extended variational principle providing the equations of motion for a system consisting of interacting classical, quasiclassical and quantum components is presented, and applied to the model of bilinear coupling. The relevant dynamical…

Quantum Physics · Physics 2009-11-13 M. Grigorescu