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arXiv · 1806.08592

Uhlmann number in translational invariant systems

Luca Leonforte·Davide Valenti·Bernardo Spagnolo·Angelo Carollo
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Abstract

We define the Uhlmann number as an extension of the Chern number, and we use this quantity to describe the topology of 2D translational invariant Fermionic systems at finite temperature. We consider two paradigmatic systems and we study the changes in their topology through the Uhlmann number. Through the linear response theory we linked two geometrical quantities of the system, the mean Uhlmann curvature and the Uhlmann number, to directly measurable physical quantities, i.e. the dynamical susceptibility and to the dynamical conductivity, respectively.

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Luca Leonforte, Davide Valenti, Bernardo Spagnolo, Angelo Carollo. 2018-06-22. Uhlmann number in translational invariant systems. https://doi.org/10.1038/s41598-019-45546-9

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