Giuseppe Del Vecchio Del Vecchio, Andrea De Luca, Alvise Bastianello
SciPost Phys. 12, 060 (2022) ·
published 14 February 2022
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We consider 1D integrable systems supporting ballistic propagation of excitations, perturbed by a localised defect that breaks most conservation laws and induces chaotic dynamics. Focusing on classical systems, we study an out-of-equilibrium protocol engineered activating the defect in an initially homogeneous and far from the equilibrium state. We find that large enough defects induce full thermalisation at their center, but nonetheless the outgoing flow of carriers emerging from the defect is non-thermal due to a generalization of the celebrated Boundary Thermal Resistance effect, occurring at the edges of the chaotic region. Our results are obtained combining ab-initio numerical simulations for relatively small-sized defects, with the solution of the Boltzmann equation, which becomes exact in the scaling limit of large, but weak defects.
Giuseppe Del Vecchio Del Vecchio, Alvise Bastianello, Andrea De Luca, Giuseppe Mussardo
SciPost Phys. 9, 002 (2020) ·
published 6 July 2020
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We study the out-of-equilibrium properties of a classical integrable
non-relativistic theory, with a time evolution initially prepared with a finite
energy density in the thermodynamic limit. The theory considered here is the
Non-Linear Schrodinger equation which describes the dynamics of the
one-dimensional interacting Bose gas in the regime of high occupation numbers.
The main emphasis is on the determination of the late-time Generalised Gibbs
Ensemble (GGE), which can be efficiently semi-numerically computed on arbitrary
initial states, completely solving the famous quench problem in the classical
regime. We take advantage of known results in the quantum model and the
semiclassical limit to achieve new exact results for the momenta of the density
operator on arbitrary GGEs, which we successfully compare with ab-initio
numerical simulations. Furthermore, we determine the whole probability
distribution of the density operator (full counting statistics), whose exact
expression is still out of reach in the quantum model.