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Differential equations on spaces of operators are very little developed in Mathematics, being in general very challenging. Here, we study a novel system of such (non-linear) differential equations. We show it has a unique solution for all…

Mathematical Physics · Physics 2025-01-22 Jean-Bernard Bru , Nathan Metraud

Quantum physics can be extended into the complex domain by considering non-Hermitian Hamiltonians that are $\mathcal{PT}$-symmetric. These exhibit exceptional points (EPs) where the eigenspectrum changes from purely real to purely imaginary…

Quantum Physics · Physics 2025-06-23 Jia-Jia Wang , Yu-Hong He , Chang-Geng Liao , Rong-Xin Chen , Jacob A. Dunningham

Quantum Information is a new area of research which has been growing rapidly since the last decade. This topic is very close to potential applications to the so called Quantum Computer. In our point of view it makes sense to develop a more…

Dynamical Systems · Mathematics 2011-04-18 A. Baraviera , C. F. Lardizabal , A. O. Lopes , M. Terra Cunha

This paper provides a connection to the non-Hermitian operators associated with the geometric potential function $s$ and Baker-Hausdorff formula. The geometric quantum potential is considered in a precise condition. The Ri-operator as a…

General Physics · Physics 2023-02-21 Jack Whongius

The Koopman operator is a mathematical tool that allows for a linear description of non-linear systems, but working in infinite dimensional spaces. Dynamic Mode Decomposition and Extended Dynamic Mode Decomposition are amongst the most…

Machine Learning · Computer Science 2021-03-26 Francesco Zanini , Alessandro Chiuso

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

Aim of this paper is trying to show the possible significance, and usefulness, of various non-selfadjoint operators for suitable Observables in non-relativistic and relativistic quantum mechanics, and in quantum electrodynamics: More…

Quantum Physics · Physics 2013-05-16 Erasmo Recami , Michel Zamboni-Rached , Ignazio Licata

In this paper we consider energy operator (a free Hamiltonian), in the second-quantized approach, for the multiparameter quon algebras: $a_{i}a_{j}^{\dagger}-q_{ij}a_{j}^{\dagger}a_{i} = \delta_{ij}, i,j\in I$ with $(q_{ij})_{i,j\in I}$ any…

Mathematical Physics · Physics 2009-11-10 Stjepan Meljanac , Ante Perica , Dragutin Svrtan

Despite acute interest in the dynamics of non-Hermitian systems, there is a lack of consensus in the mathematical formulation of non-Hermitian quantum mechanics in the community. Different methodologies are used in the literature to study…

Quantum Physics · Physics 2025-03-31 Karin Sim , Nicolò Defenu , Paolo Molignini , R. Chitra

Density matrix perturbation theory [Phys. Rev. Lett. Vol. 92, 193001 (2004)] provides an efficient framework for the linear scaling computation of response properties [Phys. Rev. Lett. Vol. 92, 193002 (2004)]. In this article, we generalize…

Computational Physics · Physics 2009-11-11 Anders M. N. Niklasson , Valery Weber , Matt Challacombe

Topological insulators have been studied intensively over the last decades. Earlier research focused on Hermitian Hamiltonians, but recently, peculiar and interesting properties were found by introducing non-Hermiticity. In this work, we…

Statistical Mechanics · Physics 2024-05-29 Chao Chen Ye , W. L. Vleeshouwers , S. Heatley , V. Gritsev , C. Morais Smith

The random matrix ensembles (RME) of quantum statistical Hamiltonian operators, {\em e.g.} Gaussian random matrix ensembles (GRME) and Ginibre random matrix ensembles (Ginibre RME), are applied to following quantum statistical systems:…

Statistical Mechanics · Physics 2007-05-23 Maciej M. Duras

The physics of systems that cannot be described by a Hermitian Hamiltonian, has been attracting a great deal of attention in recent years, motivated by their nontrivial responses and by a plethora of applications for sensing, lasing, energy…

Optics · Physics 2021-03-16 Alex Krasnok , Nikita Nefedkin , Andrea Alu

We develop a general approach for monitoring and controlling evolution of open quantum systems. In contrast to the master equations describing time evolution of density operators, here, we formulate a dynamical equation for the evolution of…

Quantum Physics · Physics 2009-08-09 M. Mohseni , A. T. Rezakhani

In this paper we obtain a description of the Hermitian operators acting on the Hilbert space $\C^n$, description which gives a complete solution to the over parameterization problem. More precisely we provide an explicit parameterization of…

Quantum Physics · Physics 2009-11-10 Petre Dita

We derive a density matrix (DM) theory for quantum cascade lasers (QCLs) that describes the influence of scattering on coherences through a generalized scattering superoperator. The theory enables quantitative modeling of QCLs, including…

Mesoscale and Nanoscale Physics · Physics 2017-08-28 Andrew Pan , Benjamin A. Burnett , Chi On Chui , Benjamin S. Williams

Reciprocal transformations of Hamiltonian operators of hydrodynamic type are investigated. The transformed operators are generally nonlocal, possessing a number of remarkable algebraic and differential-geometric properties. We apply our…

Exactly Solvable and Integrable Systems · Physics 2009-11-07 E. V. Ferapontov , M. V. Pavlov

In quantum information geometry, the curvature of von-Neumann entropy and relative entropy induce a natural metric on the space of mixed quantum states. Here we use this information metric to construct a random matrix ensemble for states…

Quantum Physics · Physics 2026-01-26 Harry J. D. Miller

It is well known that density matrices can be used in quantum mechanics to represent the information available to an observer about either a system with a random wave function (``statistical mixture'') or a system that is entangled with…

Quantum Physics · Physics 2007-05-23 Detlef Duerr , Sheldon Goldstein , Roderich Tumulka , Nino Zanghi

A Hermitian and an anti-Hermitian first-order intertwining operators are introduced and a class of $\eta$-weak-pseudo-Hermitian position-dependent mass (PDM) Hamiltonians are constructed. A corresponding reference-target…

Quantum Physics · Physics 2008-04-04 Omar Mustafa , S. Habib Mazharimousavi