The Horizons of Observability in PT-symmetric Four-site Quantum Lattices

Acta Polytechnica

M. Znojil¹ 

关键词: hidden Hermiticity;    spectra and exceptional points;    horizons;    discrete Schroedinger operators;    quantum graphs;    loops;    four-site lattices;    connectedness;    strong-coupling anomalies;   

DOI  :  

来源: Czech Technical University in Prague, Faculty of M

【 摘 要 】

One of the key merits ofPT -symmetric (i.e., parity times time reversal symmetric) quantum HamiltoniansHlies in the existence of a horizon of the stability of the system. Mathematically speaking, this horizon is formed by the boundary of the domainD (H) ⊂ RD of the (real) coupling strengths for which the spectrum of energies is real and non-degenerate, i.e., in principle, observable. It is shown here that even in the elementary circular four-site quantum lattices withD= 2 orD= 3 the domain of hidden HermiticityD (H) proves multiply connected, i.e., topologically nontrivial.

【 授权许可】

Unknown