We study the adiabatic dynamics of the Lipkin-Meshkov-Glick (LMG) model close to its quantum critical point by linearly switching the transverse field from an initial large value to zero. We concentrate our attention on the residual energy after the quench in order to characterize the level of diabaticity of the evolution. As a function of the characteristic time of the quench tau we identify three different regimes. For fast quenches the residual energy E(res) is almost independent on tau. For slower quenches a second intermediate region appears in which a powerlike decay emerges with E(res) similar to tau(-3/2). By further slowing the quench rate, we find a third large-tau regime characterized by a different power law, E(res) similar to tau(-2). All these findings can be accounted for by means of an effective Landau-Zener approximation for the finite-size LMG model. We complete our description of the adiabatic dynamics of the LMG model through the analysis of the entanglement entropy of the evolved state.

Adiabatic quantum dynamics of the Lipkin-Meshkov-Glick model / Caneva, T; Fazio, R; Santoro, Giuseppe Ernesto. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - 78:10(2008), pp. 104426.104426-1-104426.104426-8. [10.1103/PhysRevB.78.104426]

Adiabatic quantum dynamics of the Lipkin-Meshkov-Glick model

Santoro, Giuseppe Ernesto
2008-01-01

Abstract

We study the adiabatic dynamics of the Lipkin-Meshkov-Glick (LMG) model close to its quantum critical point by linearly switching the transverse field from an initial large value to zero. We concentrate our attention on the residual energy after the quench in order to characterize the level of diabaticity of the evolution. As a function of the characteristic time of the quench tau we identify three different regimes. For fast quenches the residual energy E(res) is almost independent on tau. For slower quenches a second intermediate region appears in which a powerlike decay emerges with E(res) similar to tau(-3/2). By further slowing the quench rate, we find a third large-tau regime characterized by a different power law, E(res) similar to tau(-2). All these findings can be accounted for by means of an effective Landau-Zener approximation for the finite-size LMG model. We complete our description of the adiabatic dynamics of the LMG model through the analysis of the entanglement entropy of the evolved state.
2008
78
10
104426-1
104426-8
104426
Caneva, T; Fazio, R; Santoro, Giuseppe Ernesto
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/13603
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