Dynamical freezing of relaxation to equilibrium

Iubini, Stefano and Chirondojan, Liviu Florin and Oppo, Gian-Luca and Politi, Antonio and Politi, Paolo (2019) Dynamical freezing of relaxation to equilibrium. Physical Review Letters, 122 (8). 084102. ISSN 0031-9007

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    Abstract

    We provide evidence of an extremely slow thermalization occurring in the discrete nonlinear Schrödinger model. At variance with many similar processes encountered in statistical mechanics— typically ascribed to the presence of (free) energy barriers—here the slowness has a purely dynamical origin: it is due to the presence of an adiabatic invariant, which freezes the dynamics of a tall breather. Consequently, relaxation proceeds via rare events, where energy is suddenly released towards the background. We conjecture that this exponentially slow relaxation is a key ingredient contributing to the nonergodic behavior recently observed in the negative-temperature region of the discrete nonlinear Schrödinger equation.