Excited-state quantum phase transitions studied from a non-Hermitian perspective
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389021%3A_____%2F17%3A00494834" target="_blank" >RIV/61389021:_____/17:00494834 - isvavai.cz</a>
Alternative codes found
RIV/68378271:_____/17:00487461
Result on the web
<a href="https://link.aps.org/accepted/10.1103/PhysRevA.95.010103" target="_blank" >https://link.aps.org/accepted/10.1103/PhysRevA.95.010103</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1103/PhysRevA.95.010103" target="_blank" >10.1103/PhysRevA.95.010103</a>
Alternative languages
Result language
angličtina
Original language name
Excited-state quantum phase transitions studied from a non-Hermitian perspective
Original language description
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.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10301 - Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect)
Result continuities
Project
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Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2017
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Physical Review A
ISSN
2469-9926
e-ISSN
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Volume of the periodical
95
Issue of the periodical within the volume
1
Country of publishing house
US - UNITED STATES
Number of pages
5
Pages from-to
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UT code for WoS article
000398367800001
EID of the result in the Scopus database
2-s2.0-85011655153