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We consider new concepts of entropy and pressure for stationary systems acting on density matrices which generalize the usual ones in Ergodic Theory. Part of our work is to justify why the definitions and results we describe here are…

Dynamical Systems · Mathematics 2011-08-23 A. Baraviera , C. F. Lardizabal , Artur O. Lopes , M. Terra Cunha

The Wigner function for one and two-mode quantum systems is explicitely expressed in terms of the marginal distribution for the generic linearly transformed quadratures. Then, also the density operator of those systems is written in terms…

Quantum Physics · Physics 2009-10-30 G. M. D'Ariano , S. Mancini , V. I. Man'ko , P. Tombesi

In this paper we consider density matrices operator related to non-Hermitian Hamiltonians. In particular, we analyse two natural extensions of what is usually called a density matrix operator (DM), of pure states and of the entropy…

Mathematical Physics · Physics 2025-01-22 Fabio Bagarello , Francesco Gargano , Lidia Saluto

While the partial transpose operation appears in many fundamental results in quantum theory -- such as the Peres-Horodecki criterion for entanglement detection -- a physical interpretation of the partial transpose is lacking. In this work,…

Quantum Physics · Physics 2025-08-19 James Fullwood , Junxian Li

The simulation of quantum transport in a realistic, many-particle system is a nontrivial problem with no quantitatively satisfactory solution. While real-time propagation has the potential to overcome the shortcomings of conventional…

Mesoscale and Nanoscale Physics · Physics 2015-10-16 Justin E. Elenewski , Yanxiang Zhao , Hanning Chen

The modular operator approach of Tomita-Takesaki to von Neumann algebras is elucidated in the algebraic structure of certain supersymmetric quantum mechanical systems. A von Neumann algebra is constructed from the operators of the system.…

Quantum Physics · Physics 2025-10-30 Rupak Chatterjee , Ting Yu

The Feynman integral is one of the most accurate methods for calculating density operator dynamics in open quantum systems. However, the number of time steps that can realistically be used is always limited, therefore one often obtains an…

Computational Physics · Physics 2010-12-14 Nikesh S. Dattani

We describe rigorous quantum measurement theory in the Heisenberg picture by applying operator deformation techniques previously used in noncommutative quantum field theory. This enables the conventional observables (represented by…

Mathematical Physics · Physics 2014-03-24 Andreas Andersson

We show that, by utilising temporal quantum correlations as expressed by pseudo-density operators (PDOs), it is possible to recover formally the standard quantum dynamical evolution as a sequence of teleportations in time. We demonstrate…

We define an infinite dimensional modification of lower-semicomputability of density operators by G\'acs with an attempt to fix some problem in the paper. Our attempt is partly achieved by showing the existence of universal operator under…

Information Theory · Computer Science 2016-02-22 Toru Takisaka

The absolute/relative debate on the nature of space and time is ongoing for thousands of years. Here we attempt to investigate space and time from the information theoretic point of view to understand spatial and temporal correlations under…

Quantum Physics · Physics 2021-01-22 Tian Zhang

Information plays an important role in our understanding of the physical world. We hence propose an entropic measure of information for any physical theory that admits systems, states and measurements. In the quantum and classical world,…

Quantum Physics · Physics 2010-05-04 Anthony J. Short , Stephanie Wehner

Based on a recent proof of free choices in linking equations to the experiments they describe, I clarify relations among some purely mathematical entities featured in quantum mechanics (probabilities, density operators, partial traces, and…

Quantum Physics · Physics 2014-09-15 John M. Myers

Motivated by both concepts of R.J. Adler's recent work on utilizing Clifford algebra as the linear line element $ds = \left\langle \gamma_\mu \right\rangle dX^\mu $, and the fermionization of the cylindrical worldsheet Polyakov action, we…

High Energy Physics - Theory · Physics 2016-04-27 Hsu-Wen Chiang , Yao-Chieh Hu , Pisin Chen

This paper explores the Invariant Subspace Problem in operator theory and functional analysis, examining its applications in various branches of mathematics and physics. The problem addresses the existence of invariant subspaces for bounded…

Quantum Physics · Physics 2023-06-30 Mostafa Behtouei

We generalize the concepts of Internal Time Superoperator, its associated non unitary similarity transformations and Liapounov variables, to quantum systems with diagonal singularity, and we give a constructive proof of the existence of…

Quantum Physics · Physics 2016-09-08 Roberto Laura , Adolfo R. Ordoniez

In this paper, we extend the standard formalism of quantum mechanics to a quantum theory for a total system including one internal measuring apparatus. The internality of the measuring apparatus implies that different decomposition of a…

Quantum Physics · Physics 2012-05-17 Wen-ge Wang

Several quantum systems have been used in the last few years to extend supersymmetry. In this paper we show all this systems fit into the picture of what we call "Number Operator Algebras".

Mathematical Physics · Physics 2007-05-23 Fabien Besnard

Students in quantum mechanics class are taught that the wave function contains all knowable information about an isolated system. Later in the course, this view seems to be contradicted by the mysterious density matrix, which introduces a…

General Physics · Physics 2021-04-16 Mark G. Kuzyk

We propose a series of quantum algorithms for computing a wide range of quantum entropies and distances, including the von Neumann entropy, quantum R\'{e}nyi entropy, trace distance, and fidelity. The proposed algorithms significantly…

Quantum Physics · Physics 2024-07-29 Qisheng Wang , Ji Guan , Junyi Liu , Zhicheng Zhang , Mingsheng Ying