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 one-dimensional
fermion system at zero temperature induces a universal power law $\propto
t^{-2}$ in its long-time 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 non-equilibrium
fermionic spectral function are considered. We show that the non-universal
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
long-time dynamics of the current injected from a biased probe exhibits the
same universal power law relaxation, in sharp contrast with the non-quenched
case which features a fast exponential decay of the current towards its steady
value, and thus represents a fingerprint of quench-induced dynamics. Finally,
we show that a proper tuning of the probe temperature, compared to that of the
one-dimensional channel, can enhance the visibility of the universal power-law
behaviour.