We study the multipartite entanglement of a quantum many-body system undergoing a quantum quench. We quantify the multipartite entanglement through the quantum Fisher information (QFI) density, and we are able to express it after a quench in terms of a generalised response function. For pure state initial conditions and in the thermodynamic limit, we can express the QFI as the fluctuations of an observable computed in the so-called diagonal ensemble. We apply the formalism to the dynamics of a quantum Ising chain, after a quench in the transverse field. In this model the asymptotic state is, in almost all cases, more than two-partite entangled. Moreover, starting from the ferromagnetic phase, we find a divergence of multipartite entanglement for small quenches closely connected to a corresponding divergence of the correlation length.

Multipartite entanglement after a quantum quench

Pappalardi, Silvia;Russomanno, Angelo;Silva, Alessandro;Fazio, Rosario
2017-01-01

Abstract

We study the multipartite entanglement of a quantum many-body system undergoing a quantum quench. We quantify the multipartite entanglement through the quantum Fisher information (QFI) density, and we are able to express it after a quench in terms of a generalised response function. For pure state initial conditions and in the thermodynamic limit, we can express the QFI as the fluctuations of an observable computed in the so-called diagonal ensemble. We apply the formalism to the dynamics of a quantum Ising chain, after a quench in the transverse field. In this model the asymptotic state is, in almost all cases, more than two-partite entangled. Moreover, starting from the ferromagnetic phase, we find a divergence of multipartite entanglement for small quenches closely connected to a corresponding divergence of the correlation length.
2017
2017
5
1
20
053104
http://stacks.iop.org/1742-5468/2017/i=5/a=053104
https://arxiv.org/abs/1701.05883
http://cdsads.u-strasbg.fr/abs/2017JSMTE..05.3104P
Pappalardi, Silvia; Russomanno, Angelo; Silva, Alessandro; Fazio, Rosario
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/48584
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