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Related papers: A Quantum-Theoretic Analog for a Pair of Noncommut…

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In the scheme of a quantum nondemolition (QND) measurement, an observable is measured without perturbing its evolution. In the context of studies of decoherence in quantum computing, we examine the `open' quantum system of a two-level atom,…

Quantum Physics · Physics 2009-11-13 Subhashish Banerjee , R. Ghosh

In this paper, the impact of temperature fluctuations in the entanglement of two qubits described by a spin-1/2 XX model is studied. To describe the out-of-equilibrium situation, super-statistics is used with fluctuations given by a…

Quantum Physics · Physics 2021-09-03 Jorge David Castaño-Yepes , Cristian Felipe Ramirez-Gutierrez

We examine the inference of quantum density operators from incomplete information by means of the maximization of general non-additive entropic forms. Extended thermodynamic relations are given. When applied to a bipartite spin 1/2 system,…

Quantum Physics · Physics 2015-05-20 N. Canosa , R. Rossignoli

By revisiting the path-integral formulation of the Hubbard model, we propose a theoretical approach based on a semiclassical approximation employing an unconventional coherent-state representation. Within this framework, a subset of the…

Strongly Correlated Electrons · Physics 2026-04-06 Yuki Yamasaki , Hidemaro Suwa , Cristian D. Batista , Shintaro Hoshino

In this paper, the Green function theory of quantum many-particle systems recently presented is reworked within the framework of nonextensive statistical mechanics with a new normalized $q$-expectation values. This reformulation introduces…

Condensed Matter · Physics 2009-10-31 E. K. Lenzi , R. S. Mendes , A. K. Rajagopal

The Unruh effect, predicting a thermal reservoir for accelerating systems, calls for a more refined understanding of measurement processes involving quantum systems as thermometers. Conventional models fail to account for the inherent…

Quantum Physics · Physics 2025-02-26 M. Cardi , P. Solinas , N. Zanghì

Statistical formulations of thermodynamic entropy, such as those by Boltzmann and Gibbs, were originally developed for classical systems and are well understood in that context. However, the foundational aspects of quantum statistical…

Quantum Physics · Physics 2025-10-08 Smitarani Mishra , Shaon Sahoo

A nonlinear theory of quantum Brownian motion in classical environment is developed based on a thermodynamically enhanced nonlinear Schrodinger equation. The latter is transformed via the Madelung transformation into a nonlinear quantum…

Quantum Physics · Physics 2011-04-15 Roumen Tsekov

A nonlinear dynamics semi-classical model is used to show that standard quantum spin analysis can be obtained. The model includes a classically driven nonlinear differential equation with dissipation and a semi-classical interpretation of…

Quantum Physics · Physics 2018-11-08 Joshua J. Heiner , David R. Thayer

We initially prepare a quantum linear oscillator weakly coupled to a bath in equilibrium at an arbitrary temperature. We disturb this system by varying a Hamiltonian parameter of the coupled oscillator, namely, either its spring constant or…

Statistical Mechanics · Physics 2015-05-27 Ilki Kim

An evolution equation for the expectation values of the Boltzmann factor between monomer valence bond states is derived. It contains the whole information on the thermodynamical and magnetic properties of the spin $\frac{1}{2}$ quantum…

Condensed Matter · Physics 2008-02-03 K. -H. Mütter

We calculate the conductance through a single quantum dot coupled to metallic leads, modeled by the spin 1/2 Anderson model. We adopt the finite-U extension of the noncrossing approximation method. Our results are in good agreement with…

Strongly Correlated Electrons · Physics 2007-05-23 D. Gerace , E. Pavarini , L. C. Andreani

We consider a quantum system of non-interacting fermions at temperature T, in the framework of linear response theory. We show that semiclassical theory is an appropriate framework to describe some of their thermodynamic properties, in…

Mathematical Physics · Physics 2009-11-07 Monique Combescure , Didier Robert

Despite conventional wisdom that spin-1/2 systems have no classical analog, we introduce a set of classical coupled oscillators with solutions that exactly map onto the dynamics of an unmeasured electron spin state in an arbitrary,…

Quantum Physics · Physics 2011-12-12 K. B. Wharton , R. A. Linck , C. H. Salazar-Lazaro

We investigate a non-equilibrium reaction-diffusion model and equivalent ferromagnetic spin 1/2 XY spin chain with alternating coupling constant. The exact energy spectrum and the n-point hole correlations are considered with the help of…

Statistical Mechanics · Physics 2016-08-31 Akira Fujii

In this second paper in a series, we show that the the general statistical approach to nonrelativistic quantum mechanics developed in the first paper yields a representation of quantum spin and magnetic moments based on classical…

Quantum Physics · Physics 2014-09-22 G. H. Goedecke

We use a semiclassical approximation to derive the partition function for an arbitrary potential in one-dimensional Quantum Statistical Mechanics, which we view as an example of finite temperature scalar Field Theory at a point. We rely on…

Quantum Physics · Physics 2009-10-31 C. A. A. de Carvalho , R. M. Cavalcanti

We present a model independent, operator algebraic approach to non-equilibrium quantum thermodynamics within the framework of two-dimensional Conformal Field Theory. Two infinite reservoirs in equilibrium at their own temperatures and…

High Energy Physics - Theory · Physics 2017-09-13 Stefan Hollands , Roberto Longo

We develop a semiclassical density functional theory in the context of quantum dots. Coulomb blockade conductance oscillations have been measured in several experiments using nanostructured quantum dots. The statistical properties of these…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Denis Ullmo , Tatsuro Nagano , Steven Tomsovic , Harold U. Baranger

Previous experimental realizations of Dicke model in atomic or ionic systems are based on global observables assuming uniform spin-boson coupling, while inevitable experimental nonuniformity on the one hand requires site-resolved…

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