Thermal Conductivity for a Momentum Conserving Model

Basile, Giada; Bernardin, Cedric; Olla, Stefano

Thermal Conductivity for a Momentum Conserving Model

Authors

Basile, Giada

Bernardin, Cedric

Olla, Stefano

Description

We introduce a model whose thermal conductivity diverges in dimension 1 and 2, while it remains finite in dimension 3. We consider a system of oscillators perturbed by a stochastic dynamics conserving momentum and energy. We compute thermal conductivity via Green-Kubo formula. In the harmonic case we compute the current-current time correlation function, that decay like $t^{-d/2}$ in the unpinned case and like $t^{-d/2-1}$ if a on-site harmonic potential is present. This implies a finite conductivity in $d\ge 3$ or in pinned cases, and we compute it explicitly. For general anharmonic strictly convex interactions we prove some upper bounds for the conductivity that behave qualitatively as in the harmonic cases.
Accepted for the publication in Communications in Mathematical Physics