Excited-state quantum phase transitions in the anharmonic Lipkin-Meshkov-Glick model: Dynamical aspects
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AuthorKhalouf Rivera, Jamil; Gamito, Juan; Pérez Bernal, Francisco; Arias Peñalver, José María; Pérez Fernández, Pedro
American Physical Society
Khalouf-Rivera, J., Gamito, J., Pérez-Bernal, F., Arias, J. M., & Pérez-Fernández, P. (2023). Excited-state quantum phase transitions in the anharmonic Lipkin-Meshkov-Glick model: Dynamical aspects. Physical Review E, 107(6), 064134.[DOI: 10.1103/PhysRevE.107.064134]
SponsorshipMCIN/AEI PID2019-104002GB- C22 PID2020-114687GB-I00 UHU-1262561; European Union (EU) US-1380840 P20_01247 UNHU-15CE-2848; Junta de Andalucia; Consejeria de Economia, Conocimiento, Empresas y Universidad, Junta de An- dalucia (Spain); Spanish Government; Junta de Andalucia; CEAFMC; Universidad de Huelva High Performance Computer (HPC@UHU) located in the Campus Universitario el Carmen; ERDF-A Way of Making Europe; European Union (EU) PID2019-104002GB-C21 PY2000764
The standard Lipkin-Meshkov-Glick (LMG) model undergoes a second-order ground-state quantum phase transition (QPT) and an excited-state quantum phase transition (ESQPT). The inclusion of an anharmonic term in the LMGHamiltonian gives rise to a second ESQPT that alters the static properties of the model [Gamito et al., Phys. Rev. E 106, 044125 (2022)]. In the present work, the dynamical implications associated to this new ESQPT are analyzed. For that purpose, a quantum quench protocol is defined on the system Hamiltonian that takes an initial state, usually the ground state, into a complex excited state that evolves on time. The impact of the new ESQPT on the time evolution of the survival probability and the local density of states after the quantum quench, as well as on the Loschmidt echoes and the microcanonical out-of-time-order correlator (OTOC) are discussed. The anharmonity-induced ESQPT, despite having a different physical origin, has dynamical consequences similar to those observed in the ESQPT already present in the standard LMG model.