Mpemba Meets Quantum Chaos: Anomalous Relaxation and Mpemba Crossings in Dissipative Sachdev-Ye-Kitaev Models

Abstract: The Mpemba effect (MPE), named after a student who first observed the phenomenon, has intrigued scientists for decades by showing that hot liquid can freeze faster than cold under certain conditions. Recently, analogous effects have been identified in integrable quantum systems. However, a key distinction between the classical MPE and its quantum analog is that the latter relies predominantly on the of the properties of the initial states rather than the cooling rate. In this paper, we explore the quench dynamics of Sachdev-Ye-Kitaev (SYK) systems coupled to thermal baths. We investigate three scenarios--SYK systems coupled to SYK thermal baths, SYK systems coupled to two thermal baths at different temperatures, and dissipative SYKs modeled by the Lindblad equation. In the regimes where the system and the baths are strongly coupled, we observe effective temperature oscillations and Mpemba crossings (MPCs)--the effect of temperature crossings which are absent in quasi-equilibrium thermodynamic analysis--when the system is strongly coupled to SYK thermal baths. These effects are not observed in the Liouvillian formalism. The emergence of MPCs in quantum chaotic systems exhibits strong parallels with the classical MPE.