13 papers
Inverse Feshbach's problem: Solvability and solutions
Miloslav Znojil
Given a certain specific, by matrix form of the Feshbach's effective (i.e., energy-dependent) Hamiltonian , the inverse-problem reconstruction of the…
Triple exceptional point with unitary paths of unfolding in a three-site fermionic Swanson-like model
Bijan Bagchi, Aritra Ghosh, Miloslav Znojil
A fermionic three-site generalization of the popular bosonic Swanson model is studied as providing an exactly solvable five-parametric example of the quantum-mechanical unitary-evo…
Phase transitions in quasi-Hermitian quantum models at exceptional points of order four
Miloslav Znojil
Quantum phase transition is interpreted as an evolution, at the end of which a parameter-dependent Hamiltonian loses its observability. In the language of mathematics, such…
Twin Hamiltonians, three types of the Dyson maps, and the probabilistic interpretation problem in quasi-Hermitian quantum mechanics
Aritra Ghosh, Adam Miranowicz, Miloslav Znojil
In the framework of the so-called quasi-Hermitian quantum mechanics of stationary unitary systems, bound states are usually constructed as eigenstates of a Hamilton…
Quasi-harmonic spectra from branched Hamiltonians
Aritra Ghosh, Bijan Bagchi, A. Ghose-Choudhury +2
We revisit the canonical quantization to assess the spectrum of the modified Emden equation , which is an isochronous case of…
Emergence and localization of exceptional points in an exactly solvable toy model
Miloslav Znojil
The most elementary non-Hermitian quantum square-well problem with real spectrum is considered. The Schroedinger equation is required discrete and endowed with PT-symmetric Robin (…