Generalized fluids in 1D as a wave packet gas
Andrew Urichuk (Université Paris-Cergy)
Macroscopic transport in one dimensional integrable and quasi-integrable models is characterized by a universal framework known as Generalized Hydrodynamics (GHD). In its standard, Euler-scale, form GHD mirrors the description of a two-dimensional compressible fluid, however this standard formulation neglects fluctuations (both thermal and quantum) and becomes unwieldy upon the introduction of integrability breaking effects. Instead of introducing these corrections into the evolution equations our approach is to come up with a more precise characterization of initial fluctuations, analogous to fluctuating conventional hydrodynamics. To this end I will introduce a method wherein the fluid is modeled as a gas of semiclassical wavepackets, which can easily incorporate both integrability breaking terms and a correct fluctuating extension to GHD. In this talk I will review conventional GHD and demonstrate how to implement our numerically efficient wave packet gas extension. From the wave packet gas approach I will demonstrate the presence of long-range correlations at long-times, where one-point observables appear thermal, suggesting deviation from ‘true’ thermalization at diffusive time-scales.