Quantum quench from a thermal tensor state: boundary effects and generalized Gibbs ensemble

Understand

We consider a quantum quench in a non-interacting fermionic one-dimensional field-theory.

• The system of size $L$ is initially prepared into two halves $\mathcal{L}$ ($[-L/2,0]$) and $\mathcal{R}$ ($[0,L/2]$), each of them thermalized at two different temperatures, ${T_{L}}$ and ${T_{R}}$ respectively.
• At a given time the two halves are joined together by a local coupling and the whole system is left to evolve unitarily.
• For an infinitely extended system ($L\rightarrow \infty$), we show that the time evolution of the particle and energy densities is well described via a hydrodynamic approach which allows us to evaluate the correspondent stationary currents.