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Excited-state quantum phase transitions studied from a non-Hermitian perspective
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SYSNO ASEP 0494834 Druh ASEP J - Článek v odborném periodiku Zařazení RIV Záznam nebyl označen do RIV Poddruh J Článek ve WOS Název Excited-state quantum phase transitions studied from a non-Hermitian perspective Tvůrce(i) Šindelka, Milan (UFP-V) ORCID
Santos, L.F. (US)
Moiseyev, N. (IL)Celkový počet autorů 3 Číslo článku 010103 Zdroj.dok. Physical Review A. - : American Physical Society - ISSN 2469-9926
Roč. 95, č. 1 (2017)Poč.str. 5 s. Jazyk dok. eng - angličtina Země vyd. US - Spojené státy americké Klíč. slova Excited states ; Hamiltonians ; Phase transitions 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) CEP LG15013 GA MŠMT - Ministerstvo školství, mládeže a tělovýchovy Institucionální podpora UFP-V - RVO:61389021 UT WOS 000398367800001 EID SCOPUS 85011655153 DOI 10.1103/PhysRevA.95.010103 Anotace A main distinguishing feature of non-Hermitian quantum mechanics is the presence of exceptional points (EPs). They correspond to the coalescence of two energy levels and their respective eigenvectors. Here, we use the Lipkin-Meshkov-Glick (LMG) model as a test bed to explore the strong connection between EPs and the onset of excited state quantum phase transitions (ESQPTs). We show that for finite systems, the exact degeneracies (EPs) obtained with the non-Hermitian LMG Hamiltonian continued into the complex plane are directly linked with the avoided crossings that characterize the ESQPTs for the real (physical) LMG Hamiltonian. The values of the complex control parameter alpha that lead to the EPs approach the real axis as the system size N -> infinity. This happens for both the EPs that are close to the separatrix that marks the ESQPT and also for those that are far away, although in the latter case, the convergence rate is smaller. With the method of Pade approximants, we can extract the critical value of alpha. Pracoviště Ústav fyziky plazmatu Kontakt Vladimíra Kebza, kebza@ipp.cas.cz, Tel.: 266 052 975 Rok sběru 2019 Elektronická adresa https://link.aps.org/accepted/10.1103/PhysRevA.95.010103
Počet záznamů: 1