RT Journal Article
T1 Anharmonicity-induced excited-state quantum phase transition in the symmetric phase of the two-dimensional limit of the vibron model
A1 Khalouf-Rivera, Jamil
A1 Pérez Bernal, Francisco
A1 Carvajal Zaera, Miguel
AB In most cases, excited-state quantum phase transitions can be associated with the existence of critical points (local extrema or saddle points) in a system's classical limit energy functional. However, an excited-state quantum phase transition might also stem from the lowering of the asymptotic energy of the corresponding energy functional. One such example occurs in the two-dimensional (2D) limit of the vibron model, once an anharmonic term in the form of a quadratic bosonic number operator is added to the Hamiltonian. This case has been studied in the broken-symmetry phase [Pérez-Bernal and Álvarez-Bajo, Phys. Rev. A 81, 050101 (2010)]. In the present work we delve further into the nature of this excited-state quantum phase transition and we characterize it in the symmetric phase of the model, making use of quantities such as the effective frequency, the expected value of the quantum number operator, the participation ratio, the density of states, and the quantum fidelity susceptibility. In addition to this, we extend the usage of the quasilinearity parameter, introduced in molecular physics, to characterize the phases in the spectrum of the anharmonic 2D limit of the vibron model and a practical analysis is included with the characterization of the critical energies for the linear isomers HCN and HNC.
SN 1050-2947
SN 1094-1622 (electrónico)
YR 2022
FD 2022
LK http://hdl.handle.net/10272/20846
UL http://hdl.handle.net/10272/20846
LA eng
NO Khalouf-Rivera, J., Pérez-Bernal, F., & Carvajal, M. (2022). Anharmonicity-induced excited-state quantum phase transition in the symmetric phase of the two-dimensional limit of the vibron model. In Physical Review A (Vol. 105, Issue 3). American Physical Society (APS). https://doi.org/10.1103/physreva.105.032215
NO We  acknowledge  useful  discussions  with  José  MiguelArias, Manuel Calixto, Pedro Pérez Fernández, and Lea San-tos. This project received funding from the European Union’sHorizon 2020 research and innovation program under MarieSklodowska-Curie  Grant  Agreement  No.  872081  and  fromGrant No. PID2019-104002GB-C21 funded by MCIN/AEI/10.13039/501100011033  and,  as  appropriate,  by  ERDF  Away  of  making  Europe,  by  the  European  Union,  or  by  theEuropean  Union  NextGenerationEU/PRTR.  This  work  wasalso  partially  supported  by  the  Consejería  de  Transforma-ción  Económica,  Industria,  Conocimiento  y  Universidades,Junta  de  Andalucía,  and  European  Regional  DevelopmentFund through Grants No. UHU-1262561 (J.K.-R. and F.P.-B.)and  No.  PY2000764  and  by  the  Ministerio  de  Ciencia,  In-novación y Universidades (Grant No. COOPB20364) (M.C.).Computing resources supporting this work were provided bythe CEAFMC and Universidad de Huelva High PerformanceComputer  located  at  the  Campus  Universitario  el  Carmenand funded by FEDER/MINECO Project No. UNHU-15CE-2848.
DS Repositorio Institucional de la Universidad de Huelva
RD 14 jul 2026