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arXiv · 2110.10597

Finite-temperature quantum discordant criticality

Poetri Sonya Tarabunga·Tiago Mendes-Santos·Fabrizio Illuminati·Marcello Dalmonte
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Abstract

In quantum statistical mechanics, finite-temperature phase transitions are typically governed by classical field theories. In this context, the role of quantum correlations is unclear: recent contributions have shown how entanglement is typically very short-ranged, and thus uninformative about long-ranged critical correlations. In this work, we show the existence of finite-temperature phase transitions where a broader form of quantum correlation than entanglement, the entropic quantum discord, can display genuine signatures of critical behavior. We consider integrable bosonic field theories in both two- and three-dimensional lattices, and show how the two-mode Gaussian discord decays algebraically with the distance even in cases where the entanglement negativity vanishes beyond nearest-neighbor separations. Systematically approaching the zero-temperature limit allows us to connect discord to entanglement, drawing a generic picture of quantum correlations and critical behavior that naturally describes the transition between entangled and discordant quantum matter.

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Poetri Sonya Tarabunga, Tiago Mendes-Santos, Fabrizio Illuminati, Marcello Dalmonte. 2021-10-20. Finite-temperature quantum discordant criticality. https://doi.org/10.1103/physrevb.105.075104

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