Excited-state quantum phase transitions in the two-spin elliptic Gaudin model



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Relaño Pérez, Armando and Esebbag, Carlos and Dukelsky, Jorge (2016) Excited-state quantum phase transitions in the two-spin elliptic Gaudin model. Physical review E, 94 (5). ISSN 2470-0045

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Official URL: http://dx.doi.org/10.1103/PhysRevE.94.052110


We study the integrability of the two-spin elliptic Gaudin model for arbitrary values of the Hamiltonian parameters. The limit of a very large spin coupled to a small one is well described by a semiclassical approximation with just one degree of freedom. Its spectrum is divided into bands that do not overlap if certain conditions are fulfilled. In spite of the fact that there are no quantum phase transitions in each of the band heads, the bands show excited-state quantum phase transitions separating a region in which the parity symmetry is broken from another region in which time-reversal symmetry is broken. We derive analytical expressions for the critical energies in the semiclassical approximation, and confirm the results by means of exact diagonalizations for large systems.

Item Type:Article
Additional Information:

©2016 American Physical Society. We acknowledge support from the Spanish Ministry of Economy and Competitiveness through Grants No. FIS2012-34479, No. FIS2012-35536, and from MINECO (Spain) and FEDER (Spain) Grant No. FIS2015-63770-P.

Uncontrolled Keywords:Systems
Subjects:Sciences > Physics > Thermodynamics
ID Code:42055
Deposited On:20 Apr 2017 09:20
Last Modified:20 Apr 2017 10:10

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