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The time evolution of a system with a time-dependent non-Hermitian Hamiltonian is in general unstable with exponential growth or decay. A periodic driving field may stabilize the dynamics because the eigenphases of the associated Floquet…

Quantum Physics · Physics 2015-06-11 Jiangbin Gong , Qing-hai Wang

We show that several Hamiltonians that are $\mathcal{PT}$ symmetric may be taken to Hermitian Hamiltonians via a non-unitary transformation and vice versa. We also show that for some specific Hamiltonians such non-unitary transformations…

In this work, we derive exact solutions of a dynamical equation, which can represent all two-level Hermitian systems driven by periodic $N$-step driving fields. For different physical parameters, this dynamical equation displays various…

Quantum Physics · Physics 2021-11-03 Zhi-Cheng Shi , Ye-Hong Chen , Wei Qin , Yan Xia , X. X. Yi , Shi-Biao Zheng , Franco Nori

The complex geometry underlying the Schr\"odinger dynamics of coherent states for non-Hermitian Hamiltonians is investigated. In particular two seemingly contradictory approaches are compared: (i) a complex WKB formalism, for which the…

Mathematical Physics · Physics 2012-07-12 Eva-Maria Graefe , Roman Schubert

The question of controllability is investigated for a quantum control system in which the Hamiltonian operator components carry explicit time dependence which is not under the control of an external agent. We consider the general situation…

Quantum Physics · Physics 2009-11-10 Chunhua Lan , Tzyh-Jong Tarn , Quo-Shin Chi , John W. Clark

Two coupled two-level systems placed under external time-dependent magnetic fields are modeled by a general Hamiltonian endowed with a symmetry that enables us to reduce the total dynamics into two independent two-dimensional sub-dynamics.…

Quantum Physics · Physics 2016-09-20 R. Grimaudo , A. Messina , H. Nakazato

We study a non-interacting quantum particle, moving on a one-dimensional lattice, which is subjected to repetitive measurements. We investigate the consequence when such motion is interrupted and restarted from the same initial…

Quantum Physics · Physics 2023-03-21 Ranjan Modak , S. Aravinda

The time-dependent Schrodinger equation is solved for two model problems for a non-Hermitian quantum system.A simple matrix model system is used to examine two critical problems for these systems: complex and non-observable energies and…

Quantum Physics · Physics 2024-12-11 Brian L Burrows

Schroedinger equation on a Hilbert space ${\cal H}$, represents a linear Hamiltonian dynamical system on the space of quantum pure states, the projective Hilbert space $P {\cal H}$. Separable states of a bipartite quantum system form a…

Quantum Physics · Physics 2009-11-13 Nikola Buric

We review some recent results of the so-called quasi-hermitian quantum mechanics, with particular focus on the quantum dynamics both in the Schr\"odinger and in the Heisenberg representations. The role of Krein spaces is also discussed.

Functional Analysis · Mathematics 2012-02-06 Fabio Bagarello , Miloslav Znojil

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

Adiabatic processes driven by non-Hermitian, time-dependent Hamiltonians may be sped up by generalizing inverse engineering techniques based on Berry's transitionless driving algorithm or on dynamical invariants. We work out the basic…

Quantum Physics · Physics 2015-09-18 S. Ibáñez , S. Martínez-Garaot , Xi Chen , E. Torrontegui , J. G. Muga

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

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

For a large class of time-dependent non-Hermitain Hamiltonians expressed in terms linear and bilinear combinations of the generators for an Euclidean Lie-algebra respecting different types of PT-symmetries, we find explicit solutions to the…

Quantum Physics · Physics 2019-01-17 Andreas Fring , Thomas Frith

We discuss the relationship between exact solvability of the Schr\"{o}dinger equation with a position-dependent mass and the ordering ambiguity in the Hamiltonian operator within the frame of supersymmetric quantum mechanics. The…

Quantum Physics · Physics 2009-11-07 Besire Gonul , Bulent Gonul , Dilek Tutcu , Okan Ozer

It is noted that the Schrodinger equation with any self-adjoint Hamiltonian is unitary equivalent to a set of non-interacting classical harmonic oscillators and in this sense any quantum dynamics is completely integrable. Higher order…

Mathematical Physics · Physics 2019-11-06 Igor V. Volovich

Models of disorder with a direction (constant imaginary vector-potential) are considered. These non-Hermitian models can appear as a result of computation for models of statistical physics using transfer matrix technique or describe…

Disordered Systems and Neural Networks · Physics 2009-10-30 K. B. Efetov

We consider quantum dynamics of systems with fast spatial modulation of the Hamiltonian. Employing the formalism of supersymmetric quantum mechanics and decoupling fast and slow spatial oscillations we demonstrate that the effective…

Quantum Physics · Physics 2019-04-10 Viktor Novičenko , Julius Ruseckas , Egidijus Anisimovas

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