Berlin 2018 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 35: Nonequilibrium Quantum Many-Body Systems I (joint session TT/DY)
DY 35.4: Talk
Wednesday, March 14, 2018, 10:30–10:45, H 3010
Non-monotonic response and light-cone freezing in gapless-to-(partially) gapped quantum quenches of fermionic systems — •Sergio Porta1,2, Filippo Maria Gambetta1,2, Niccolò Traverso Ziani3, Dante Marvin Kennes4, Maura Sassetti1,2, and Fabio Cavaliere1,2 — 1Dipartimento di Fisica, Università di Genova, Genova, 16146 Italy — 2SPIN-CNR, Genova, 16146 Italy — 3Institute for Theoretical Physics and Astrophysics, University of Würzburg, 97074 Würzburg, Germany — 4Department of Physics, Columbia University, New York, NY 10027, USA
The properties of prototypical examples of one-dimensional fermionic systems undergoing a sudden quantum
quench from a gapless state to a (partially) gapped state are analyzed. By means of a Generalized Gibbs
Ensemble analysis or by numerical solutions in the interacting cases, we observe an anomalous, non-monotonic
response of steady state correlation functions as a function of the strength of the mechanism opening the gap.
In order to interpret this result, we calculate the full dynamical evolution of these correlation functions, which
shows a freezing of the propagation of the quench information (light cone) for large quenches. We argue that
this freezing is responsible for the non-monotonous behaviour of observables. In continuum non-interacting
models, this freezing can be traced back to a Klein-Gordon equation in the presence of a source term. We conclude
by arguing in favour of the robustness of the phenomenon in the cases of non-sudden quenches and higher
dimensionality.
arXiv:1708.09320