2007/01/30 by Miloslav Znojil
Physics and Astronomy · #Quantum Mechanics and Non-Hermitian Physics #Quantum chaos and dynamical systems #quant-ph
paper · pdf · doi:10.1016/j.physletb.2007.01.046
published as Phys. Lett. B 647 (2007) 225 - 230 · 14 pp., 1 fig
arxiv created 2007/01/30 · openalex publication_date 2007/02/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Many indefinite-metric (often called pseudo-Hermitian or PT-symmetric) quantum models H prove "physical" (i.e., Hermitian with respect to an innovated, ad hoc scalar product) inside a characteristic domain of parameters D. This means that the energies get complex (= unobservable) beyond the boundary (= Kato's "exceptional points", EPs). In a solvable example we detect an enlargement of D caused by the emergence of a new degree of freedom. We conjecture that such a beneficial mechanism of a return to the real spectrum near EPs may be generic and largely model-independent.