Alessio Calzona, Filippo Maria Gambetta, Matteo Carrega, Fabio Cavaliere, Thomas L. Schmidt, Maura Sassetti
SciPost Phys. 4, 023 (2018) ·
published 10 May 2018

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It has been shown that a quantum quench of interactions in a onedimensional
fermion system at zero temperature induces a universal power law $\propto
t^{2}$ in its longtime dynamics. In this paper we demonstrate that this
behaviour is robust even in the presence of thermal effects. The system is
initially prepared in a thermal state, then at a given time the bath is
disconnected and the interaction strength is suddenly quenched. The
corresponding effects on the long times dynamics of the nonequilibrium
fermionic spectral function are considered. We show that the nonuniversal
power laws, present at zero temperature, acquire an exponential decay due to
thermal effects and are washed out at long times, while the universal behaviour
$\propto t^{2}$ is always present. To verify our findings, we argue that these
features are also visible in transport properties at finite temperature. The
longtime dynamics of the current injected from a biased probe exhibits the
same universal power law relaxation, in sharp contrast with the nonquenched
case which features a fast exponential decay of the current towards its steady
value, and thus represents a fingerprint of quenchinduced dynamics. Finally,
we show that a proper tuning of the probe temperature, compared to that of the
onedimensional channel, can enhance the visibility of the universal powerlaw
behaviour.