A Chain, a Bath, a Sink, and a Wall

Entropy

Roberto Livi¹  Stefano Iubini¹  Antonio Politi²  Stefano Lepri³  Gian-Luca Oppo⁴ 

[1] Dipartimento di Fisica e Astronomia, Università di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino, Italy;Institute for Complex Systems and Mathematical Biology & SUPA, University of Aberdeen, Aberdeen AB24 3UE, UK;Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino, Italy;SUPA and Department of Physics, University of Strathclyde, Glasgow G4 0NG, UK;

关键词: discrete nonlinear schrödinger;    discrete breathers;    negative temperatures;    open systems;   

DOI  :  10.3390/e19090445

来源: DOAJ

【 摘 要 】

We numerically investigate out-of-equilibrium stationary processes emerging in a Discrete Nonlinear Schrödinger chain in contact with a heat reservoir (a bath) at temperature T L and a pure dissipator (a sink) acting on opposite edges. Long-time molecular-dynamics simulations are performed by evolving the equations of motion within a symplectic integration scheme. Mass and energy are steadily transported through the chain from the heat bath to the sink. We observe two different regimes. For small heat-bath temperatures T L and chemical-potentials, temperature profiles across the chain display a non-monotonous shape, remain remarkably smooth and even enter the region of negative absolute temperatures. For larger temperatures T L, the transport of energy is strongly inhibited by the spontaneous emergence of discrete breathers, which act as a thermal wall. A strongly intermittent energy flux is also observed, due to the irregular birth and death of breathers. The corresponding statistics exhibit the typical signature of rare events of processes with large deviations. In particular, the breather lifetime is found to be ruled by a stretched-exponential law.

【 授权许可】

Unknown