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arXiv · 1002.2842

Long time dynamics following a quench in an integrable quantum spin chain: local versus non-local operators and effective thermal behavior

Davide Rossini·Sei Suzuki·Giuseppe Mussardo·Giuseppe E. Santoro·Alessandro Silva
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Abstract

We study the dynamics of the quantum Ising chain following a zero-temperature quench of the transverse field strength. Focusing on the behavior of two-point spin correlation functions, we show that the correlators of the order parameter display an effective asymptotic thermal behavior, i.e., they decay exponentially to zero, with a phase coherence rate and a correlation length dictated by the equilibrium law with an effective temperature set by the energy of the initial state. On the contrary, the two-point correlation functions of the transverse magnetization or the density-of-kinks operator decay as a power-law and do not exhibit thermal behavior. We argue that the different behavior is linked to the locality of the corresponding operator with respect to the quasi-particles of the model: non-local operators, such as the order parameter, behave thermally, while local ones do not. We study which features of the two-point correlators are a consequence of the integrability of the model by analizing their robustness with respect to a sufficiently strong integrability-breaking term.

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Davide Rossini, Sei Suzuki, Giuseppe Mussardo, Giuseppe E. Santoro, Alessandro Silva. 2010-10-12. Long time dynamics following a quench in an integrable quantum spin chain: local versus non-local operators and effective thermal behavior. https://doi.org/10.1103/physrevb.82.144302

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