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The theory of noncommutative dynamical entropy and quantum symbolic dynamics for quantum dynamical systems is analised from the point of view of quantum information theory. Using a general quantum dynamical system as a communication channel…

Quantum Physics · Physics 2009-11-07 Robert Alicki

We construct a complete set of Wannier functions which are localized at both given positions and momenta. This allows us to introduce the quantum phase space, onto which a quantum pure state can be mapped unitarily. Using its probability…

Statistical Mechanics · Physics 2015-06-10 Xizhi Han , Biao Wu

We briefly review the use of unitary evolution as a uniqueness criterion in the selection of quantum representations, in the context of scalar fields in non-stationary situations.

General Relativity and Quantum Cosmology · Physics 2013-11-05 Jeronimo Cortez , Guillermo A. Mena Marugan , Javier Olmedo , Jose M. Velhinho

In the Entropic Dynamics framework the dynamics is driven by maximizing entropy subject to appropriate constraints. In this work we bring Entropic Dynamics one step closer to full equivalence with quantum theory by identifying constraints…

Quantum Physics · Physics 2018-06-19 Nicholas Carrara , Ariel Caticha

The quantum dynamics of optomechanical systems was mostly studied for their fluctuations around classical steady states. We present a theoretical approach to determining the system observables of optomechanical systems as genuine quantum…

Quantum Physics · Physics 2012-06-21 Bing He

Cosmology is an attracting subject for students but usually difficult to deal with if general relativity is not known. In this article, we first recall the Newtonian derivation of the Friedmann equations which govern the dynamics of our…

Physics Education · Physics 2009-11-07 Jean-Philippe Uzan , Roland Lehoucq

Regarding the strange properties of quantum entropy and entanglement, e.g., the negative quantum conditional entropy, we revisited the foundations of quantum entropy, namely, von Neumann entropy, and raised the new method of quantum…

Quantum Physics · Physics 2012-05-08 Dong-Sheng Wang

We prove sharp universal upper bounds on the number of steady and asymptotic states of discrete- and continuous-time Markovian evolutions of open quantum systems. We show that the bounds depend only on the dimension of the system and not on…

Quantum Physics · Physics 2024-06-26 Daniele Amato , Paolo Facchi

For a quantum state undergoing unitary Schr\"odinger time evolution, the von Neumann entropy is constant. Yet the second law of thermodynamics, and our experience, show that entropy increases with time. Ingarden introduced the quantum…

Quantum Physics · Physics 2019-07-03 Craig S. Lent

We derive generic upper bounds on the rate of purity change and entropy increase for open quantum systems. These bounds depend solely on the generators of the nonunitary dynamics and are independent of the particular states of the systems.…

Quantum Physics · Physics 2014-08-07 Raam Uzdin , Eric Lutz , Ronnie Kosloff

We show that the rate of increase of von Neumann entropy computed from the reduced density matrix of an open quantum system is an excellent indicator of the dynamical behavior of its classical hamiltonian counterpart. In decohering quantum…

Quantum Physics · Physics 2015-06-26 W. H. Zurek , J. P. Paz

Open quantum systems are governed by both unitary and non-unitary dynamics, with dissipation arising from the latter. Traditional quantum divergence measures, such as quantum relative entropy, fail to account for the non-unitary oriented…

Quantum Physics · Physics 2025-09-23 Tomohiro Nishiyama , Yoshihiko Hasegawa

The time-dependence of correlation functions under the influence of classical equations of motion is described by an exact evolution equation. For conservative systems thermodynamic equilibrium is a fixed point of these equations. We show…

High Energy Physics - Theory · Physics 2009-10-30 Christof Wetterich

The dynamics of an atom on the Jaynes-Cummings model has been studied by an atomic inversion, von Neumann entropy and so on. In this letter, we will treat the Jaynes-Cummings model as a problem in non-equilibrium statistical mechanics and…

Quantum Physics · Physics 2011-04-15 Shigeru Furuichi , Masanori Ohya , Hiroki Suyari

Having a broad range of methods available for implementing unitary operations is crucial for quantum information tasks. We study a dissipative process commonly used to describe dissipatively coupled systems and show that the process can…

Quantum Physics · Physics 2020-02-12 C. Arenz , A. Metelmann

Discussions of quantum mechanics often loosely claim that time evolution logically must be unitary, in order for the probabilistic interpretation of the amplitudes of the state vector to make sense at all times. We discuss from first…

Quantum Physics · Physics 2025-02-25 Edward Parker

Our point of departure are the unitary dynamics of closed quantum systems as generated from the Schr\"odinger equation. We focus on a class of quantum models that typically exhibit roughly exponential relaxation of some observable within…

Quantum Physics · Physics 2011-12-23 Christian Bartsch , Jochen Gemmer

Any real interaction process produces many incompatible system versions, or realisations, giving rise to omnipresent dynamic randomness and universally defined complexity (arXiv:physics/9806002). Since quantum behaviour dynamically emerges…

General Physics · Physics 2014-01-30 Andrei P. Kirilyuk

In quantum mechanics without application of any superselection rule to the set of the observables, a closed quantum system temporally evolves unitarily, and this Lorentzian regime is characterized by von Neumann entropy of exactly zero. In…

Quantum Physics · Physics 2023-04-03 Eiji Konishi

The nonequilibrium dynamics of coupled quantum oscillators subject to different time dependent quenches are analyzed in the context of the Liouville-von Neumann approach. We consider models of quantum oscillators in interaction that are…

High Energy Physics - Theory · Physics 2009-11-07 G. Flores-Hidalgo , Rudnei O. Ramos