Nonmonotonic response and light-cone freezing in fermionic systems under quantum quenches from gapless to gapped or partially gapped states.
Porta S., Gambetta F.M., Traverso Ziani N., Kennes D.M., Sassetti M., Cavaliere F.
II - Fisica della materia
Aula 32B-2 - Giovedì 20 h 09:00 - 13:00
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The properties of prototypical examples of one-dimensional fermionic systems undergoing a sudden quantum quench from a gapless to a gapped state are analyzed, both in integrable and non-integrable models. We observe an anomalous, nonmonotonic 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 for large quenches. In noninteracting models, this freezing can be traced back to a Klein-Gordon equation in the presence of a source term.