(PhD pre-defense)

 

In my dissertation I study the nonequilibrium behavior of an integrable quantum field theory, namely the sine-Gordon model, within the framework of Generalized Hydrodynamics (GHD). A prerequisite for applying GHD is having full control of the thermodynamic Bethe Ansatz (TBA) description of the model.

 

In this presentation, I outline the derivation of the TBA for the sine-Gordon model for general rational values of the coupling constant. Employing the principles of GHD, I compute ballistic and diffusive transport coefficients. Remarkably, some of these coefficients exhibit a fractal dependence on the coupling, indicating anomalous transport exponents within the system.

 

Then I present the results of an extensive numerical investigation of the cumulant generating functions of the lowest lying conserved charges, exhibiting a similar fractal dependence. The numerical findings are corroborated thorugh analytical cross-checks in regimes where exact results are available.

 

Finally, I examine the solution of the GHD time-evolution equations for an initially localized topological charge bump. I discuss the observation that energy and charge propagate with distinct velocities, depsite being carried by the same particles – a similar phenomenon to spin-charge separation.