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We introduce a quantum phase space representation for the orientation state of extended quantum objects, using the Euler angles and their conjugate momenta as phase space coordinates. It exhibits the same properties as the standard Wigner…

Quantum Physics · Physics 2013-06-11 Timo Fischer , Clemens Gneiting , Klaus Hornberger

Starting with the quasi-Bell states of the qubit-oscillator system, we obtain time evolution of the density matrix under the adiabatic approximation. The composite density matrix leads to, via partial tracing of the qubit degree of freedom,…

Quantum Physics · Physics 2015-02-11 R. Chakrabarti , B. Virgin Jenisha

Classical surfaces in phase space correspond to quantum states in Hilbert space. Subsystems specify factor spaces of the Hilbert space. An entangled state corresponds semiclassically to a surface that cannot be decomposed into a product of…

Quantum Physics · Physics 2007-05-23 A. M. Ozorio de Almeida

Using the remarkable mathematical construct of Eugene Wigner to visualize quantum trajectories in phase space, quantum processes can be described in terms of a quasi-probability distribution analogous to the phase space probability…

Quantum Physics · Physics 2013-01-29 Frank Kirtschig , Jorrit Rijnbeek , Jeroen van den Brink , Carmine Ortix

General relation is derived which expresses the fidelity of quantum dynamics, measuring the stability of time evolution to small static variation in the hamiltonian, in terms of ergodicity of an observable generating the perturbation as…

Quantum Physics · Physics 2009-11-07 Tomaz Prosen

We discuss how the language of wave functions (state vectors) and associated non-commuting Hermitian operators naturally emerges from classical mechanics by applying the inverse Wigner-Weyl transform to the phase space probability…

Quantum Physics · Physics 2021-01-27 Pieter W. Claeys , Anatoli Polkovnikov

We estimate the quantum state of a light beam from results of quantum homodyne measurements performed on identically prepared pulses. The state is represented through the Wigner function, a ``quasi-probability density'' on $\mathbb{R}^{2}$…

Statistics Theory · Mathematics 2011-06-23 Madalin Guta , Luis Artiles

The work distribution is a fundamental quantity in nonequilibrium thermodynamics mainly due to its connection with fluctuations theorems. Here we develop a semiclassical approximation to the work distribution for a quench process in chaotic…

Quantum Physics · Physics 2017-05-17 Ignacio García-Mata , Augusto J. Roncaglia , Diego A. Wisniacki

We propose the Wigner separability entropy as a measure of complexity of a quantum state. This quantity measures the number of terms that effectively contribute to the Schmidt decomposition of the Wigner function with respect to a chosen…

Quantum Physics · Physics 2012-05-23 Giuliano Benenti , Gabriel G. Carlo , Tomaz Prosen

Using linear invariant operators in a constructive way we find the most general thermal density operator and Wigner function for time-dependent generalized oscillators. The general Wigner function has five free parameters and describes the…

Quantum Physics · Physics 2007-05-23 Sang Pyo Kim , Don N. Page

Wigner's quasi-probability distribution function in phase-space is a special (Weyl) representation of the density matrix. It has been useful in describing quantum transport in quantum optics; nuclear physics; decoherence (eg, quantum…

High Energy Physics - Theory · Physics 2008-11-26 Cosmas K Zachos

Polarization quasiprobability distribution defined in the Stokes space shares many important properties with the Wigner function for the position and momentum. Most notably, they both give correct one-dimensional marginal probability…

Quantum Physics · Physics 2017-08-16 K. Yu. Spasibko , M. V. Chekhova , F. Ya. Khalili

In this work, we consider the phase-space picture of quantum mechanics. We then introduce non-negative Wigner-like (operational) distributions \widetilde{\mathcal W}_{rho;alpha}(x,p) corresponding to the density operator \hat{rho} and being…

Statistical Mechanics · Physics 2019-06-21 Ilki Kim

Using the Wigner-Vlasov formalism, an exact 3D solution of the Schr\"odinger equation for a scalar particle in an electromagnetic field is constructed. Electric and magnetic fields are non-uniform. According to the exact expression for the…

Quantum Physics · Physics 2024-06-13 E. E. Perepelkin , B. I. Sadovnikov , N. G. Inozemtseva , P. V. Afonin

The Wigner function of a finite-dimensional system can be constructed via dual pairing of a density matrix with the Stratonovich-Weyl kernel. Following Kenfack and $\dot{\text{Z}}$yczkowski, we consider the indicator of nonclassicality of a…

Quantum Physics · Physics 2021-12-30 Vahagn Abgaryan , Arsen Khvedelidze , Astghik Torosyan

Using a model Hamiltonian for a single-mode electromagnetic field interacting with a nonlinear medium, we show that quantum expectation values of subsystem observables can exhibit remarkably diverse ergodic properties even when the dynamics…

Quantum Physics · Physics 2007-06-21 C. Sudheesh , S. Lakshmibala , V. Balakrishnan

The quantum electromagnetic (EM) field is formulated in the Weyl-Wigner representation (WW), which is equivalent to the standard Hilbert space one (HS). In principle it is possible to interpret within WW all experiments involving the EM…

General Physics · Physics 2024-12-19 Emilio Santos

The Wigner distribution function is a quasi-probability distribution. When properly integrated, it provides the correct charge and current densities, but it gives negative probabilities in some points and regions of the phase space.…

Quantum Physics · Physics 2015-08-13 E. Colomés , Z. Zhan , X. Oriols

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

We discuss an approach to determine averages of the work, dissipated heat and variation of internal energy of an open quantum system driven by an external classical field. These quantities are measured by coupling the quantum system to a…

Quantum Physics · Physics 2022-03-23 Paolo Solinas , Mirko Amico , Nino N. Zanghì