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We study non Hermitian quantum systems in noncommutative space as well as a \cal{PT}-symmetric deformation of this space. Specifically, a \mathcal{PT}-symmetric harmonic oscillator together with iC(x_1+x_2) interaction is discussed in this…

High Energy Physics - Theory · Physics 2009-03-12 Pulak Ranjan Giri , P Roy

Motivated by the recent advances in modelling the pseudo-Hermitian Hamiltonian (pHH) systems using superconducting qubits we analyze their quantum dynamics subject to a small time-dependent perturbation. In particular, We develop the linear…

Quantum Physics · Physics 2022-11-03 L. Tetling , M. V. Fistul , Ilya M. Eremin

The Heisenberg picture for non-Hermitian but $\eta$-pseudo-Hermitian Hamiltonian systems is suggested. If a non-Hermitian but $\eta$-pseudo-Hermitian Hamiltonian leads to real second order equations of motion, though their first order…

Quantum Physics · Physics 2016-04-14 Yan-Gang Miao , Zhen-Ming Xu

It is well known that an (in general, non-commutative) set of non-Hermitian operators $\Lambda_j$ with real eigenvalues need not necessarily represent observables. We describe a specific class of quantum models in which these operators plus…

Quantum Physics · Physics 2022-08-02 Miloslav Znojil

In the framework of the so-called quasi-Hermitian quantum mechanics of stationary unitary systems, bound states are usually constructed as eigenstates $|\psi_n \rangle$ of a Hamiltonian operator $H$ with real spectrum which is…

Quantum Physics · Physics 2026-01-21 Aritra Ghosh , Adam Miranowicz , Miloslav Znojil

Large families of Hamiltonians that are non-Hermitian in the conventional sense have been found to have all eigenvalues real, a fact attributed to an unbroken PT symmetry. The corresponding quantum theories possess an unconventional scalar…

Quantum Physics · Physics 2009-11-11 Zafar Ahmed , Carl M. Bender , M. V. Berry

Quantum mechanics of closed, unitary quantum systems can be formulated in non-Hermitian interaction picture (NIP) in which both the states and the observables vary with time. Then, in general, not only the Schr\"{o}dinger-equation…

Quantum Physics · Physics 2025-11-27 Miloslav Znojil

We identify quantum geometric bounds for observables in non-Hermitian systems. We find unique bounds on non-Hermitian quantum geometric tensors, generalized two-point response correlators, conductivity tensors, and optical weights. We…

Quantum Physics · Physics 2025-12-30 Milosz Matraszek , Wojciech J. Jankowski , Jan Behrends

Examples are given of non-Hermitian Hamiltonian operators which have a real spectrum. Some of the investigated operators are expressed in terms of the generators of the Weil-Heisenberg algebra. It is argued that the existence of an…

Quantum Physics · Physics 2009-09-29 João da Providência , Natália Bebiano , João Pinheiro da Providência

We in this paper demonstrate that the $PT$-symmetric non-Hermitian Hamiltonian for a periodically driven system can be generated from a kernel Hamiltonian by a generalized gauge transformation. The kernel Hamiltonian is Hermitian and…

Quantum Physics · Physics 2022-09-07 Yan Gu , Xiao-Lei Hao , J. -Q. Liang

Within CPT-symmetric quantum mechanics the most elementary differential form of the charge operator C is assumed. A closed-form integrability of the related coupled differential self-consistency conditions and a natural embedding of the…

Mathematical Physics · Physics 2009-05-18 Emanuela Caliceti , Francesco Cannata , Miloslav Znojil , Alberto Ventura

In PT quantum mechanics a fundamental principle of quantum mechanics, that the Hamiltonian must be hermitian, is replaced by another set of requirements, including notably symmetry under PT, where P denotes parity and T denotes time…

We show that a Dicke-type pseudo-hermitian Hamiltonian undergoes quantum phase transition by mapping it to the "Dressed Dicke Model" through a similarity transformation. We find the positive-definite metric in the Hilbert space of the…

Quantum Physics · Physics 2009-08-14 Tetsuo Deguchi , Pijush K. Ghosh

We extend the application of the techniques developed within the framework of the pseudo-Hermitian quantum mechanics to study a unitary quantum system described by an imaginary PT-symmetric potential v(x) having a continuous real spectrum.…

Quantum Physics · Physics 2009-11-11 Ali Mostafazadeh

We demonstrate that genuinely non-Hermitian topological phases and corresponding topological phase transitions can be naturally realized in monitored quantum circuits, exemplified by the paradigmatic non-Hermitian Su-Schrieffer-Heeger…

Mesoscale and Nanoscale Physics · Physics 2022-08-26 Christoph Fleckenstein , Alberto Zorzato , Daniel Varjas , Emil J. Bergholtz , Jens H. Bardarson , Apoorv Tiwari

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

We address the breakdown of the bulk-boundary correspondence observed in non-Hermitian systems, where open and periodic systems can have distinct phase diagrams. The correspondence can be completely restored by considering the Hamiltonian's…

Mesoscale and Nanoscale Physics · Physics 2019-05-24 Loic Herviou , Jens H. Bardarson , Nicolas Regnault

We consider a two-level system such as a two-level atom, interacting with a cavity field mode in the rotating wave approximation, when the atomic transition frequency or the field mode frequency is periodically driven in time. We show that…

The non-Hermitian formalism is used at present in many papers for the description of open quantum systems. A special language developed in this field of physics which makes it difficult for many physicists to follow and to understand the…

Quantum Physics · Physics 2018-12-11 Hichem Eleuch , Ingrid Rotter

PT-symmetric Hamiltonians and transfer matrices arise naturally in statistical mechanics. These classical and quantum models often require the use of complex or negative weights and thus fall outside of the conventional equilibrium…

Mathematical Physics · Physics 2015-06-11 Peter N. Meisinger , Michael C. Ogilvie