2024/06/21 by Stefano Iubini, Antonio Politi, Iubini, Stefano +1 · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · Chemistry · #nanoparticles nucleation surface interactions #Advanced Thermodynamics and Statistical Mechanics #Chemical Thermodynamics and Molecular Structure
paper · doi:10.48550/arxiv.2406.15140
The observation of negative-temperature states in the localized phase of the Discrete Nonlinear Schrödinger (DNLS) equation has challenged statistical mechanics for a long time. For isolated systems, they can emerge as stationary extended states through a large-deviation mechanism occurring for finite sizes, while they are formally unstable in grand-canonical setups, being associated to an unlimited growth of the condensed fraction. Here, we show that negative-temperature states in open setups are metastable and their lifetime τ is exponentially long with the temperature, τ≈ exp(λ|T|) (for T<0). A general expression for λ is obtained in the case of a simplified stochastic model of non-interacting particles. In the DNLS model, the presence of an adiabatic invariant, makes λ even larger because of the resulting freezing of the breather dynamics. This mechanism, based on the existence of two conservation laws, provides a new perspective over the statistical description of condensation processes.