Počet záznamů: 1
Perturbation Theory Near Degenerate Exceptional Points
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SYSNO ASEP 0532599 Druh ASEP J - Článek v odborném periodiku Zařazení RIV J - Článek v odborném periodiku Poddruh J Článek ve WOS Název Perturbation Theory Near Degenerate Exceptional Points Tvůrce(i) Znojil, Miloslav (UJF-V) RID, ORCID, SAI Celkový počet autorů 1 Číslo článku 1309 Zdroj.dok. Symmetry-Basel. - : MDPI
Roč. 12, č. 8 (2020)Poč.str. 17 s. Forma vydání Tištěná - P Jazyk dok. eng - angličtina Země vyd. CH - Švýcarsko Klíč. slova non-Hermitian quantum dynamics ; unitary vicinity of exceptional points ; degenerate perturbation theory ; Hilbert-space geometry near EPs Vědní obor RIV BE - Teoretická fyzika Obor OECD Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect) Způsob publikování Open access Institucionální podpora UJF-V - RVO:61389005 UT WOS 000567698700001 EID SCOPUS 85089935096 DOI 10.3390/sym12081309 Anotace In an overall framework of quantum mechanics of unitary systems a rather sophisticated new version of perturbation theory is developed and described. The motivation of such an extension of the list of the currently available perturbation-approximation recipes was four-fold: (1) its need results from the quick growth of interest in quantum systems exhibiting parity-time symmetry (PT-symmetry) and its generalizations. (2) in the context of physics, the necessity of a thorough update of perturbation theory became clear immediately after the identification of a class of quantum phase transitions with the non-Hermitian spectral degeneracies at the Kato's exceptional points (EP). (3) in the dedicated literature, the EPs are only being studied in the special scenarios characterized by the spectral geometric multiplicityLequal to one. (4) apparently, one of the decisive reasons may be seen in the complicated nature of mathematics behind the L >= 2 constructions. In our present paper we show how to overcome the latter, purely technical obstacle. The temporarily forgotten class of the L>1 models is shown accessible to a feasible perturbation-approximation analysis. In particular, an emergence of a counterintuitive connection between the value ofL, the structure of the matrix elements of perturbations, and the possible loss of the stability and unitarity of the processes of the unfolding of the singularities is given a detailed explanation. Pracoviště Ústav jaderné fyziky Kontakt Markéta Sommerová, sommerova@ujf.cas.cz, Tel.: 266 173 228 Rok sběru 2021 Elektronická adresa https://doi.org/10.3390/sym12081309
Počet záznamů: 1