In this review, we analyse different aspects concerning the possibility to separate a gravity-
matter system into a part which lives close to a quasi-classical state and a “small” quantum …

A diagonalizable non-Hermitian Hamiltonian having a real spectrum may be used to define
a unitary quantum system, if one modifies the inner product of the Hilbert space properly. We …

We give a pedagogical introduction to time-independent scattering theory in one dimension
focusing on the basic properties and recent applications of transfer matrices. In particular …

Abstract For a non-Hermitian Hamiltonian H possessing a real spectrum, we introduce a
canonical orthonormal basis in which a previously introduced unitary map** of H to a …

Computer modeling and simulation (M&S) allows engineers to study and analyze complex
systems. Discrete-event system (DES)-M&S is used in modern management, industrial …

This research focuses on exploring the relativistic quantum dynamics of spin-0 scalar
massive charged particles within the framework of the relativistic Feshbach-Villars oscillator …

We study the quantum cosmology of a flat Friedmann–Lemaître–Robertson–Walker
Universe filled with a (free) massless scalar field and a perfect fluid that represents radiation …

For many quantum models an apparent non-Hermiticity of observables just corresponds to
their hidden Hermiticity in another, physical Hilbert space. For these models we show that …

The quantum measurement axiom dictates that physical observables and in particular the
Hamiltonian must be diagonalizable and have a real spectrum. For a time-independent …

A non-Hermitian operator with a real spectrum and a complete set of eigenvectors may
serve as the Hamiltonian operator for a unitary quantum system provided that one makes an …