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Quantum systems with a non-conserved probability can be described by means of non-Hermitian Hamiltonians and non-unitary dynamics. In this paper, the case in which the degrees of freedom can be partitioned in two subsets with light and…

Quantum Physics · Physics 2016-10-21 Alessandro Sergi

We propose a simple method of combined synchronous modulations to generate the analytically exact solutions for a parity-time symmetric two-level system. Such exact solutions are expressible in terms of simple elementary functions and…

Quantum Physics · Physics 2017-06-07 Xiaobing Luo , Baiyuan Yang , Xiaofei Zhang , Lei Li , Xiaoguang Yu

Open classical and quantum systems with effective parity-time ($\mathcal{PT}$) symmetry, over the past five years, have shown tremendous promise for advances in lasers, sensing, and non-reciprocal devices. And yet, how such effective…

Quantum Physics · Physics 2020-10-21 Archak Purkayastha , Manas Kulkarni , Yogesh N. Joglekar

We study the localization transition in periodically driven one-dimensional non-Hermitian lattices where the piece-wise two-step drive is constituted by uniform coherent tunneling and incommensurate onsite gain and loss. We find that the…

Quantum Physics · Physics 2022-03-14 C. M. Dai , Yunbo Zhang , Xuexi Yi

We associate the stationary harmonic oscillator with time-dependent systems exhibiting non-Hermiticity by means of point transformations. The new systems are exactly solvable, with all-real spectrum, and transit to the Hermitian…

Quantum Physics · Physics 2021-08-26 Kevin Zelaya , Oscar Rosas-Ortiz

We study several classes of non-Hermitian Hamiltonian systems, which can be expressed in terms of bilinear combinations of Euclidean Lie algebraic generators. The classes are distinguished by different versions of antilinear (PT)-symmetries…

Quantum Physics · Physics 2014-04-29 Sanjib Dey , Andreas Fring , Thilagarajah Mathanaranjan

We study the coupled even number of microcavities with the balanced gain and loss between any pair of their neighboring components. The effective non-Hermitian Hamiltonian for such structure has the cyclic permutation-time symmetry with…

Quantum Physics · Physics 2015-03-26 Bing He , Liu Yang , Zhaoyang Zhang , Min Xiao

Conventional manipulations over quantum systems for such as coherent population trapping and unidirectional transfer focus on Hamiltonian engineering while regarding the system's manifold geometry and constraint equation as secondary…

Quantum Physics · Physics 2025-09-08 Zhu-yao Jin , Jun Jing

We consider a non-Hermitian Hamiltonian in order to effectively describe a two-level system coupled to a generic dissipative environment. The total Hamiltonian of the model is obtained by adding a general anti-Hermitian part, depending on…

Quantum Physics · Physics 2013-10-25 Alessandro Sergi , Konstantin G. Zloshchastiev

The description of states and dynamics in non-Hermitian systems is fundamentally linked to the choice of an appropriate theoretical framework -- a point of ongoing debate in the field. This work addresses this issue by proposing a…

Quantum Physics · Physics 2026-05-07 Fei Wang , Guoying Liang , Zecheng Zhao , Bao-Ming Xu

We propose a procedure to obtain exact analytical solutions to the time-dependent Schr\"{o}dinger equations involving explicit time-dependent Hermitian Hamitonians from solutions to time-independent non-Hermitian Hamiltonian systems and the…

Quantum Physics · Physics 2017-01-25 Andreas Fring , Thomas Frith

While non-Hermitian systems are normally constructed through incoherent coupling to a larger environment, recent works have shown that under certain conditions coherent couplings can be used to similar effect. We show that this new paradigm…

Applied Physics · Physics 2022-10-21 Noah Flemens , Jeffrey Moses

We investigate a quantum mechanical system on a noncommutative space for which the structure constant is explicitly time-dependent. Any autonomous Hamiltonian on such a space acquires a time-dependent form in terms of the conventional…

Quantum Physics · Physics 2014-10-15 Sanjib Dey , Andreas Fring

Despite its long history, a canonical formulation of quantum ergodicity that applies to general classes of quantum dynamics, including driven systems, has not been fully established. Here we introduce and study a notion of quantum…

Quantum Physics · Physics 2024-12-10 Saúl Pilatowsky-Cameo , Iman Marvian , Soonwon Choi , Wen Wei Ho

In recent works we have used quantum tools in the analysis of the time evolution of several macroscopic systems. The main ingredient in our approach is the self-adjoint Hamiltonian $H$ of the system $\Sc$. This Hamiltonian quite often, and…

Quantum Physics · Physics 2019-10-23 Fabio Bagarello

We study the generalized Jaynes-Cummings model of quantum optics at the inversion-symmetry-breaking and in the ultrastrong coupling regime. With the help of a generalized multiphoton rotating-wave approximation, we study the stationary…

Quantum Physics · Physics 2015-06-16 H. K. Avetissian , G. F. Mkrtchian

Exceptional points, the spectral degeneracy points in the complex parameter space, are fundamental to non-Hermitian quantum systems. The dynamics of non-Hermitian systems in the presence of exceptional points differ significantly from those…

Quantum Physics · Physics 2021-01-29 Chon-Fai Kam , Yang Chen

We investigate in this paper time-dependent non-Hermitian Hamiltonians, which consist respectively of SU(1,1) and SU(2) generators. The former Hamiltonian is PT symmetric but the latter one is not. A time-dependent non-unitary operator is…

Quantum Physics · Physics 2022-07-12 Nadjat Amaouche , Maroua Sekhri , Rahma Zerimeche , Maamache Mustapha , J. -Q. Liang

Extended quantum mechanics using non-Hermitian, pseudo-Hermitian Hamiltonians is briefly reviewed. Supersymmetric regularizations, solvable simulations and large-N expansion techniques are recollected as suitable means for the study of…

Quantum Physics · Physics 2009-11-10 Miloslav Znojil

We find that a broken PT-symmetry operator when interacts with suitable Hermitian operator, new system becomes completely un-broken PT symmetry. Further on varying the contribution of Hermiticity one can delay or control the broken…

Quantum Physics · Physics 2020-04-14 Biswanath Rath