Regensburg 2025 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

DY: Fachverband Dynamik und Statistische Physik

DY 9: Statistical Physics far from Thermal Equilibrium

DY 9.1: Vortrag

Montag, 17. März 2025, 15:00–15:15, H47

From Hamiltonian dynamics to entropy production: A harmonic chain model — •Amir Abbasi and Roland Netz — Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany

Deriving macroscopic thermodynamic potentials, particularly entropy, from microscopic reversible dynamics remains one of the key challenges in statistical physics.

In this work, we study a one-dimensional infinite harmonic chain partitioned into a system and two baths, evolving under Hamiltonian dynamics. We derive exact expressions for the entropy production of both the system and the baths. In particular, we discuss two cases, namely, tNEQ (a transient non-equilibrium state with a Boltzmann steady-state distribution) and sNEQ (a steady non-equilibrium state with a non-Boltzmann distribution).

In tNEQ, the total entropy eventually plateaus due to the vanishing heat transfer among the system and the baths in the long-time limit, consistent with equilibration to Boltzmann statistics. However, in sNEQ, entropy increases linearly with time in the long-time limit, driven by non-vanishing heat transfer between the baths mediated by the system [1]. Consequently, persistent cross-correlations among the degrees of freedom maintain a non-Boltzmann steady-state distribution without external driving. This work bridges microscopic dynamics and thermodynamics in closed harmonic systems with infinite baths [2].

[1] Netz, R. J. Chem. Phys. 148, 18 (2018).

[2] Netz, R. Phys. Rev. E 101, 022120 (2020).

Keywords: Hamiltonian dynamics; Entropy production; Non-equilibrium thermodynamics; Closed-system thermodynamics; Harmonic chain