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We introduce, for the first time, bicoherent-state path integration as a method for quantizing non-hermitian systems. Bicoherent-state path integrals arise as a natural generalization of ordinary coherent-state path integrals, familiar from…

Mathematical Physics · Physics 2020-10-07 F. Bagarello , J. Feinberg

We study a non-Hermitian two-level system with square-wave modulated dissipation and coupling. Based on the Floquet theory, we achieve an effective Hamiltonian from which the boundaries of the $\mathcal{PT}$ phase diagram are captured…

Quantum Physics · Physics 2020-08-18 Liwei Duan , Yan-Zhi Wang , Qing-Hu Chen

We produce an exact solution of the Schr\"odinger equation for the generalized time dependent Swanson oscillator. The system studied is a non-Hermitian setup characterized by time dependent complex coefficients. The exact solution is…

Quantum Physics · Physics 2023-05-10 B. M. Villegas-Martinez , H. M. Moya-Cessa , F. Soto-Eguibar

We introduce an extended version of the Swanson model, defined on a two-dimensional non commutative space, which can be diagonalized exactly by making use of pseudo-bosonic operators. Its eigenvalues are explicitly computed and the…

Mathematical Physics · Physics 2018-10-11 Fabio Bagarello , Francesco Gargano , Salvatore Spagnolo

Non-hermitian, $\mathcal{PT}$-symmetric Hamiltonians, experimentally realized in optical systems, accurately model the properties of open, bosonic systems with balanced, spatially separated gain and loss. We present a family of exactly…

Quantum Physics · Physics 2015-12-17 Kaustubh S. Agarwal , Rajeev K. Pathak , Yogesh N. Joglekar

Reconstructing the Hamiltonian of a quantum system is an essential task for characterizing and certifying quantum processors and simulators. Existing techniques either rely on projective measurements of the system before and after coherent…

We provide time-evolution operators, gauge transformations and a perturbative treatment for non-Hermitian Hamiltonian systems, which are explicitly time-dependent. We determine various new equivalence pairs for Hermitian and non-Hermitian…

Quantum Physics · Physics 2009-11-13 Carla Figueira de Morisson Faria , Andreas Fring

The Swanson model is an exactly solvable model in quantum mechanics with a manifestly non self-adjoint Hamiltonian whose eigenvalues are all real. Its eigenvectors can be deduced easily, by means of suitable ladder operators. This is…

Quantum Physics · Physics 2020-12-30 Fabio Bagarello

The time evolution of a closed quantum system is connected to its Hamiltonian through Schroedinger's equation. The ability to estimate the Hamiltonian is critical to our understanding of quantum systems, and allows optimization of control.…

The not necessarily unitary evolution operator of a finite dimensional quantum system is studied with the help of a projection operators technique. Applying this approach to the Schr\"odinger equation allows the derivation of an alternative…

Quantum Physics · Physics 2018-08-08 V. Semin , F. Petruccione

We study symmetries of open bosonic systems in the presence of laser pumping. Non-Hermitian Hamiltonians describing these systems can be parity-time (${\cal{PT}}$) symmetric in special cases only. Systems exhibiting this symmetry are…

Quantum Physics · Physics 2020-11-23 Ewelina Lange , Grzegorz Chimczak , Anna Kowalewska-Kudłaszyk , Karol Bartkiewicz

$\mathcal{PT}$-symmetric quantum mechanics has been considered an important theoretical framework for understanding physical phenomena in $\mathcal{PT}$-symmetric systems, with a number of $\mathcal{PT}$-symmetry related applications. This…

Quantum Physics · Physics 2019-12-25 Da-Jian Zhang , Qing-hai Wang , Jiangbin Gong

We introduce a new class of quantum models with time-dependent Hamiltonians of a special scaling form. By using a couple of time-dependent unitary transformations, the time evolution of these models is expressed in terms of related systems…

Quantum Physics · Physics 2009-11-07 L. Samaj

In this article, we review the general quantum mechanical setting associated to a non self-adjoint Hamiltonian with real spectrum. Spectral properties of the Hamiltonian of a simple model of the Swanson type are investigated. The…

Quantum Physics · Physics 2019-01-30 N. Bebiano , J. da Providência

I review how methods from mesoscopic physics can be applied to describe the multiple wave scattering and complex wave dynamics in non-hermitian PT-symmetric resonators, where an absorbing region is coupled symmetrically to an amplifying…

Quantum Physics · Physics 2013-04-18 Henning Schomerus

A new method for computing exact conformal partial wave expansions is developed and applied to approach the problem of Hilbert space (Wightman) positivity in a non-perturbative four-dimensional quantum field theory model. The model is based…

High Energy Physics - Theory · Physics 2007-05-23 N. M. Nikolov , K. -H. Rehren , I. T. Todorov

The Double Green Function Formalism has been extensively used in dealing with the thermodynamics of quantum systems which evolved in time under the action of a given self-adjoint Hamiltonian. In this work, we extend the formalism to include…

Quantum Physics · Physics 2022-12-27 Romina Ramírez , Marta Reboiro

An accurate description of the nonequilibrium dynamics of systems with coupled spin and bosonic degrees of freedom remains theoretically challenging, especially for large system sizes and in higher than one dimension. Phase space methods…

Quantum Gases · Physics 2017-09-13 A. Piñeiro Orioli , A. Safavi-Naini , M. L. Wall , A. M. Rey

Over the past decade, non-Hermitian, $\mathcal{PT}$-symmetric Hamiltonians have been investigated as candidates for both, a fundamental, unitary, quantum theory, and open systems with a non-unitary time evolution. In this paper, we…

Quantum Physics · Physics 2018-01-26 Yogesh N. Joglekar , Franck Assogba Onanga , Andrew K. Harter

In this study, we introduce a two dimensional complex harmonic oscillator potential with space and time reflection symmetries. The corresponding time independent Schr\"odinger equation yields real eigenvalues with complex eigenfunctions. We…

Quantum Physics · Physics 2020-12-09 Masoumeh Izadparast , S. Habib Mazharimousavi