A chain, a bath, a sink and a wall

Iubini, Stefano and Lepri, Stefano and Livi, Roberto and Oppo, Gian-Luca and Politi, Antonio (2017) A chain, a bath, a sink and a wall. Entropy, 19 (9). 445. ISSN 1099-4300

[thumbnail of Iubibi-etal-Entropy2017-A-chain-a-bath-a-sink-and-a-wall]
Text (Iubibi-etal-Entropy2017-A-chain-a-bath-a-sink-and-a-wall)
Final Published Version
License: Creative Commons Attribution 4.0 logo

Download (4MB)| Preview


    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 TL 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 TL 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 TL, 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.

    ORCID iDs

    Iubini, Stefano, Lepri, Stefano, Livi, Roberto, Oppo, Gian-Luca ORCID logoORCID: https://orcid.org/0000-0002-5376-4309 and Politi, Antonio;