@article{10272/21797,
year = {2022},
url = {https://hdl.handle.net/10272/21797},
abstract = {The basic Lipkin-Meshkov-Glick model displays a second-order ground-state quantum phase transition and an excited-state quantum phase transition (ESQPT). The inclusion of an anharmonic term in the Hamiltonian implies a second ESQPT of a different nature. We characterize this ESQPT using the mean field limit of the model. The alternative ESQPT, associated with the changes in the boundary of the finite Hilbert space of the system, can be properly described using the order parameter of the ground-state quantum phase transition, the energy gap between adjacent states, the participation ratio, and the quantum fidelity susceptibility.},
organization = {TheauthorsthankJoséEnriqueGarcíaRamosandMiguel CarvajalZaeraforfruitfulandinspiringdiscussionson thetopicofthispaper.ThisworkispartoftheI+ D+iProjectsNo.PID2019-104002GB-C21,No.PID2019104002GB-C22,andNo.PID2020-114687GB-I00funded byGrantNo.MCIN/AEI/10.13039/501100011033.This workwasalsopartiallysupportedbytheConsejeríade Conocimiento,InvestigaciónyUniversidad,JuntadeAndalucíaandEuropeanRegionalDevelopmentFund(ERDF), GrantsNo.UHU-1262561andNo.US-1380840anditisalso partofgrantgroupsFQM-160andFQM-287andtheproject PAIDI2020ProjectNo.P20_01247,fundedbytheConsejeríadeEconomía,Conocimiento,EmpresasyUniversidad, JuntadeAndalucía(Spain)andERDF—AWayofMaking Europe,bytheEuropeanUnionorbytheEuropeanUnion NextGenerationEU/PRTR.Computingresourcessupporting thisworkwereprovidedbytheCEAFMCandUniversidadde HuelvaHighPerformanceComputerlocatedintheCampus UniversitarioelCarmenandfundedbyFEDER/MINECO ProjectNo.UNHU-15CE-2848.},
publisher = {American Physical Society},
title = {Excited-state quantum phase transitions in the anharmonic Lipkin-Meshkov-Glick model: Static aspects},
doi = {10.1103/physreve.106.044125},
author = {Gamito, J. and Khalouf-Rivera, Jamil and Arias Carrasco, José Miguel and Pérez Fernández, Pedro and Pérez Bernal, Francisco},
}