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arXiv · 1908.06374

Response of macroscopic and microscopic dynamical quantifiers to the quantum critical region

Stav Haldar·Saptarshi Roy·Titas Chanda·Aditi Sen De
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Abstract

At finite temperatures, the quantum critical region (QCR) emerges as a consequence of the interplay between thermal and quantum fluctuations. We seek for suitable physical quantities, which during dynamics can give prominent response to QCR in the transverse field quantum $XY$ model. We report that the maximum energy absorbed, the nearest neighbor entanglement and the quantum mutual information of the time evolved state after a quench of the transverse magnetic field exhibits a faster fall off with temperature when the initial magnetic field is taken from within the QCR, compared to the choice of the initial point from different phases. We propose a class of dynamical quantifiers, originated from the response of these physical quantities and show that they can faithfully mimic the equilibrium physics, namely detection of the QCR at finite temperatures.

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Stav Haldar, Saptarshi Roy, Titas Chanda, Aditi Sen De. 2019-08-18. Response of macroscopic and microscopic dynamical quantifiers to the quantum critical region. https://doi.org/10.1103/physrevresearch.2.033249

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