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arXiv · 0708.2978

Entanglement Entropy in Extended Quantum Systems

John Cardy
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Abstract

After a brief introduction to the concept of entanglement in quantum systems, I apply these ideas to many-body systems and show that the von Neumann entropy is an effective way of characterising the entanglement between the degrees of freedom in different regions of space. Close to a quantum phase transition it has universal features which serve as a diagnostic of such phenomena. In the second part I consider the unitary time evolution of such systems following a `quantum quench' in which a parameter in the hamiltonian is suddenly changed, and argue that finite regions should effectively thermalise at late times, after interesting transient effects.

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John Cardy. 2007-08-22. Entanglement Entropy in Extended Quantum Systems. https://doi.org/10.1140/epjb/e2008-00102-5

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