Transport in the sine-Gordon field theory: from generalized hydrodynamics to semiclassics

Understand

The semiclassical approach introduced by Sachdev and collaborators proved to be extremely successful in the study of quantum quenches in massive field theories, both in homogeneous and inhomogeneous settings.

• While conceptually very simple, this method allows one to obtain analytic predictions for several observables when the density of excitations produced by the quench is small.
• At the same time, a novel generalized hydrodynamic (GHD) approach, which captures exactly many asymptotic features of the integrable dynamics, has recently been introduced.
• Interestingly, also this theory has a natural interpretation in terms of semiclassical particles and it is then natural to compare the two approaches.