Universal scaling of quench-induced correlations in a one-dimensional channel at finite temperature

• Published in: arXiv.org 2018-04
• Main Authors: Calzona, Alessio, Gambetta, Filippo Maria, Carrega, Matteo, Cavaliere, Fabio, Schmidt, Thomas L, Sassetti, Maura
• Format: Article
• Language: English
• Subjects: Decay rate; Dynamics; Fermions; Power law; Quenching; Temperature effects; Transport properties; Visibility
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1711.02967

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.