ABSTRACT: We study the time evolution of the reduced density operator for a class of quantum Brownian motion models consisting of a particle moving in a potential V (x) and coupled to an environment of harmonic oscillators in a thermal state. Our principle tool is the Wigner function of the reduced density operator, and for linear systems we derive an explicit expression for the Wigner function...

This letter considers the problem of detecting and characterizing a target buried beneath a rough surface separating two homogeneous half spaces. The problem of detecting the target is tackled by analyzing the frequency-averaged Wigner–Ville function, the purpose of which is to filter out rough surface scattering. Characterization of the target is performed using the iterative solution derived ...

We derive the kinetic equations for both the covariant and equal-time Wigner functions of Dirac particles with electromagnetic, scalar and pseudoscalar interactions. We emphasize the constraint equations for the spinor components in the equal-time formulation. PACS: 03.65.Bz, 05.60.+w, 52.60.+h. Typeset using REVTEX 1 One of the recent progresses in transport theory [1,2] is the establishment o...

© 2017 Muddassar Rashid et al., published by De Gruyter Open. This work is licensed under the Creative Commons AttributionNonCommercial-NoDerivs 4.0 License. Quantum Meas. Quantum Metrol. 2017; 4:17–25 Research Article Open Access Muddassar Rashid, Marko Toroš, and Hendrik Ulbricht* Wigner Function Reconstruction in Levitated Optomechanics https://doi.org/10.1515/qmetro-2017-0003 Received July ...

The application of Wigner distribution (WD)-based signal synthesis to signal separation problems is often adversely affected by WD interference terms. We present a modified signal synthesis method where the use of a masked WD allows the definition of don’t-care regions. In the don’t-care regions, detrimental interference terms (whose timefrequency location is assumed to be known) are ignored. T...

The nano-era of semiconductor electronics introduces the necessity of simulation methods which describe the electron transport in ultra-small devices in a mixed mode where quantumcoherent processes are considered along with the de-coherence processes of scattering. The latter can be conveniently described in the Wigner picture of quantum mechanics, however the coherent counterpart gives rise to...

The integral of the Wigner function over a subregion of the phase-space of a quantum system may be less than zero or greater than one. It is shown that for systems with one degree of freedom, the problem of determining the best possible upper and lower bounds on such an integral, over all possible states, reduces to the problem of finding the greatest and least eigenvalues of an hermitian opera...

A phase space formulation of the filtering process upon an incident quantum state is developed. This formulation can explain the results of both quantum interference and delayed-choice experiments without making use of the controversial wave-particle duality. Quantum particles are seen as localized and indivisible concentrations of energy and/or mass, their probability amplitude in phase space ...

This paper is concerned with a synthesis study of the fast Fourier transform (FFT), the short time Fourier transform (STFT and the Wigner distribution (WD) in analysing the phonocardiogram signal (PCG) or heart cardiac sounds.     The FFT (Fast Fourier Transform) can provide a basic understanding of the frequency contents of the heart sounds. The STFT is obtained by calculating the Fourier tran...

We present a review of the applications of the Wigner distribution function in various areas of signal processing: amplitude and phase retrieval, signal recognition, characterization of arbitrary signals, optical systems and devices, and coupling coefficient estimation in phase space. Although reference is made to specific signals and systems, the mathematical formulation is general and can be ...