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arXiv · 0805.4149

Complexity of thermal states in quantum spin chains

Marko Znidaric·Tomaz Prosen·Iztok Pizorn
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Abstract

We study quantum correlations and complexity of simulation, characterized by quantum mutual information and entanglement entropy in operator space respectively, for thermal states in critical, non-critical and quantum chaotic spin chains. A simple general relation between the two quantities is proposed. We show that in all cases mutual information and entanglement entropy saturate with the system size, whereas as a function of the inverse temperature, we find logarithmic divergences for critical cases and uniform bounds in non-critical cases. A simple efficient quasi-exact method for computation of arbitrary entropy related quantities in thermalized XY spin chains is proposed.

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Marko Znidaric, Tomaz Prosen, Iztok Pizorn. 2008-08-12. Complexity of thermal states in quantum spin chains. https://doi.org/10.1103/physreva.78.022103

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