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The mixed density operator for coarsegrained eigenlevels of a static Hamiltonian is represented in phase space by the spectral Wigner function, which has its peak on the corresponding classical energy shell. The action of trajectory…

Quantum Physics · Physics 2024-03-05 Alfredo M. Ozorio de Almeida

The Wigner-Weyl isomorphism for quantum mechanics on a compact simple Lie group $G$ is developed in detail. Several New features are shown to arise which have no counterparts in the familiar Cartesian case. Notable among these is the notion…

Quantum Physics · Physics 2009-11-10 N. Mukunda , G. Marmo , Alessandro Zampini , S. Chaturvedi , R. Simon

A formalism is presented in which quantum particle dynamics can be developed on its own rather than `quantization' of an underlying classical theory. It is proposed that the unification of probability and dynamics should be considered as…

Quantum Physics · Physics 2007-05-23 Tulsi Dass

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

Semiclassical Mechanics allows for a description of quantum systems which preserves their phase information, while using only the system's classical dynamics as an input. Over the time an identification has been developed between stationary…

Quantum Physics · Physics 2021-02-16 Kush Mohan Mittal , Olivier Giraud , Denis Ullmo

Based on a geometric picture, the example of free particle motion for both classical and quantum domains is considered in the tomographic probability representation. Wave functions and density operators as well as optical and symplectic…

Quantum Physics · Physics 2011-12-01 Vladimir I. Man'ko , Franco Ventriglia

We show that the quantum wavefunction, interpreted as the probability density of finding a single non-localized quantum particle, which evolves according to classical laws of motion, is an intermediate description of a material quantum…

Quantum Physics · Physics 2007-05-23 Daniela Dragoman

This work presents a selective review of results concerning the mathematical interface between the classical and quantum aspects encountered in problems such as the nuclear mean-field dynamics or quantum Brownian motion. It is shown that…

Quantum Physics · Physics 2018-01-09 M. Grigorescu

Within the framework of the probability representation of quantum mechanics, we study a superposition of generic Gaussian states associated to symmetries of a regular polygon of n sides; in other words, the cyclic groups (containing the…

Quantum Physics · Physics 2022-03-16 Julio A. López-Saldívar , Vladimir I. Man'ko , Margarita A. Man'ko

The quasiprobability distribution of the discrete Wigner function provides a complete description of a quantum state and is, therefore, a useful alternative to the usual density matrix description. Moreover, the experimental quantum state…

Quantum Physics · Physics 2023-10-13 Deepesh Khushwani , Priya Batra , V. R. Krithika , T. S. Mahesh

The Lindblad equation governs general markovian evolution of the density operator in an open quantum system. An expression for the rate of change of the Wigner function as a sum of integrals is one of the forms of the Weyl representation…

Quantum Physics · Physics 2009-11-07 Alfredo M. Ozorio de Almeida

In this work we have explored few tools in Quantum State Tomography for Continuous Variable Systems. The concept of quantum states in phase space representation is introduced in a simple manner by using a few statistical concepts. Unlike…

Quantum Physics · Physics 2019-12-12 Ludmila Botelho

The existing relation between the tomographic description of quantum states and the convolution algebra of certain discrete groupoids represented on Hilbert spaces will be discussed. The realizations of groupoid algebras based on qudit,…

Mathematical Physics · Physics 2015-06-17 A. Ibort , V. I. Manko , G. Marmo , A. Simoni , C. Stornaiolo

We introduce a numerical method to simulate nonlinear open quantum dynamics of a particle in situations where its state undergoes significant expansion in phase space while generating small quantum features at the phase-space Planck scale.…

Starting from a new principle inspired by quantum tomography rather than from Born's rule, this paper gives a self-contained deductive approach to quantum mechanics and quantum measurement. A suggestive notion for what constitutes a quantum…

Quantum Physics · Physics 2024-05-22 Arnold Neumaier

Drawing inspiration from Dirac's work on functions of non commuting observables, we develop a fresh approach to phase space descriptions of operators and the Wigner distribution in quantum mechanics. The construction presented here is…

Quantum Physics · Physics 2007-05-23 S. Chaturvedi , E. Ercolessi , G. Marmo , G. Morandi , N. Mukunda , R. Simon

We present an experimental scanning-based tomography approach for near-term quantum devices. The underlying method has previously been introduced in an ensemble-based NMR setting. Here we provide a tutorial-style explanation along with…

Quantum Physics · Physics 2024-12-04 Amit Devra , Niklas J. Glaser , Dennis Huber , Steffen J. Glaser

Starting from the Pauli Hamiltonian operator, we derive a scalar quantum kinetic equations for spin-1/2 systems. Here the regular Wigner two-state matrix is replaced by a scalar distribution function in extended phase space. Apart from…

Quantum Gases · Physics 2010-04-21 Jens Zamanian , Mattias Marklund , Gert Brodin

The behaviour of classical mechanical systems is characterised by their phase portraits, the collections of their trajectories. Heisenberg's uncertainty principle precludes the existence of sharply defined trajectories, which is why…

Quantum Physics · Physics 2013-01-28 Ole Steuernagel , Dimitris Kakofengitis , Georg Ritter

The Wigner function of quantum systems is an effective instrument to construct the approximate classical description of the systems for which the classical approximation is possible. During the last time, the Wigner function formalism is…

Quantum Physics · Physics 2009-11-10 Constantin V. Usenko