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The nonequilibrium dynamics in chaotic quantum systems denies a fully understanding up to now, even if thermalization in the long-time asymptotic state has been explained by the eigenstate thermalization hypothesis which assumes a universal…

Statistical Mechanics · Physics 2020-12-08 Xinxin Yang , Pei Wang

Nondegenerate covariance, correlation and spectral density matrices are necessarily symmetric or Hermitian and positive definite. The main contribution of this paper is the development of statistical data depths for collections of Hermitian…

Methodology · Statistics 2019-11-12 Joris Chau , Hernando Ombao , Rainer von Sachs

Non-hermitian systems have gained a lot of interest in recent years. However, notions of chaos and localization in such systems have not reached the same level of maturity as in the Hermitian systems. Here, we consider non-hermitian…

Disordered Systems and Neural Networks · Physics 2022-10-19 Soumi Ghosh , Sparsh Gupta , Manas Kulkarni

The theory of orbital magnetization is reconsidered by defining additional quantities that incorporate a non-Hermitian effect due to anomalous operators that break the domain of definition of the Hermitian Hamiltonian. As a result, boundary…

Mesoscale and Nanoscale Physics · Physics 2020-01-08 K. Kyriakou , K. Moulopoulos

We introduce kernel density machines (KDM), an agnostic kernel-based framework for learning the Radon-Nikodym derivative (density) between probability measures under minimal assumptions. KDM applies to general measurable spaces and avoids…

Machine Learning · Statistics 2026-03-27 Andrea Della Vecchia , Damir Filipovic , Paul Schneider

In this work we present a general formalism to treat non-Hermitian and noncommutative Hamiltonians. This is done employing the phase-space formalism of quantum mechanics, which allows to write a set of robust maps connecting the Hamitonians…

Quantum Physics · Physics 2019-08-15 Jonas F. G. Santos , Fabricio. S. Luiz , Oscar. S. Duarte , Miled. H. Y. Moussa

It is shown that, in the framework of non-relativistic quantum mechanics, any conserved Hermitian operator (which may depend explicitly on the time) is the generator of a one-parameter group of unitary symmetries of the Hamiltonian and…

Quantum Physics · Physics 2015-10-19 G. F. Torres del Castillo , J. E. Herrera Flores

We propose two different strategies to find eigenvalues and eigenvectors of a given, not necessarily Hermitian, matrix $A$. Our methods apply also to the case of complex eigenvalues, making the strategies interesting for applications to…

Mathematical Physics · Physics 2020-06-24 Fabio Bagarello , Francesco Gargano

We extend and explore the general non-relativistic effective theory of dark matter (DM) direct detection. We describe the basic non-relativistic building blocks of operators and discuss their symmetry properties, writing down all…

High Energy Physics - Phenomenology · Physics 2015-06-04 A. Liam Fitzpatrick , Wick Haxton , Emanuel Katz , Nicholas Lubbers , Yiming Xu

Most recently it has been observed e.g. by Bender and Klevansky (arXiv:0905.4673 [hep-th]) that the C-operator related to a PT-symmetric non-Hermitian Hamilton operator is not unique. Moreover it has been remarked by Shi and Sun…

High Energy Physics - Theory · Physics 2009-06-09 F. Kleefeld

We introduce and systematically develop the theory of \emph{quantum doubly stochastic operators}, i.e. positive, trace-preserving maps on non-commutative $L_p$-spaces associated to semifinite von Neumann algebras. After establishing basic…

Operator Algebras · Mathematics 2026-05-19 Emma Sulaver

We study the most general continuous transformation on the generators of bilinear master equations of a quantum oscillator. We find that transformation operators that preserve the hermiticity of density operators and conserve the…

Quantum Physics · Physics 2017-02-23 B. A. Tay

In this paper, we explore the non-Hermitian transition matrix and its gravity dual. States in quantum field theories or gravity theories are typically prepared using Euclidean path integrals. We demonstrate that it is both natural and…

High Energy Physics - Theory · Physics 2024-06-12 Wu-zhong Guo , Tao Liu

It is widely believed that statistical interpretation of quantum mechanics requires that density operators representing quantum states be normalized. We present a description of selective measurements in terms of density operators. The…

Mathematical Physics · Physics 2007-11-15 Wlodzimierz M. Tulczyjew

A non-Hermitian operator that is related to its adjoint through a similarity transformation is defined as a pseudo-Hermitian operator. We study the level-statistics of a pseudo-Hermitian Dicke Hamiltonian that undergoes Quantum Phase…

Quantum Physics · Physics 2009-11-06 Tetsuo Deguchi , Pijush K. Ghosh , Kazue Kudo

In this paper, we investigate the spectral projection of density matrices in quantum field theory. With appropriate regularization, the spectral projectors of density matrices are expected to be well-defined. These projectors can be…

High Energy Physics - Theory · Physics 2025-08-29 Wu-zhong Guo

The density operator is usually defined starting from a set of kets in the Hilbert space and a probability distribution. From this definition it is easy to obtain a factorization of a given density operator, here called density factor (DF).…

Quantum Physics · Physics 2024-06-25 Gianfranco Cariolaro , Edi Ruffa

Standard quantum mechanics predicts the non-conservation of state norms and probability when the fundamental requirement of the Hermiticity of the Hamiltonian is relaxed. Biorthogonal quantum mechanics, or the more general metric formalism,…

Quantum Physics · Physics 2025-07-18 Mario Gonzalez , Karin Sim , R. Chitra

In principle, non-Hermitian quantum equations of motion can be formulated using as a starting point either the Heisenberg's or the Schr\"odinger's picture of quantum dynamics. Here it is shown in both cases how to map the algebra of…

Quantum Physics · Physics 2011-02-07 Alessandro Sergi

Non-Hermitian optics has revealed a series of counterintuitive phenomena with profound implications for sensing, lasing, and light manipulation. While the non-Hermiticity of Hamitonians is well-recognized, recent advancements in…

Optics · Physics 2024-04-19 Jipeng Xu , Yuanhao Mao , Jianfa Zhang , Biao Yang , Ken Liu , Zhihong Zhu