Finite time interaction quench in a Luttinger model

Abstract

We analyze the dynamics of a Luttinger model following a quench in the electron-electron interaction strength, where the change in the interaction strength occurs over a finite time scale $τ$. We study the Loschmidt echo (the overlap between the initial and final state) as a function of time, both numerically and within a perturbation scheme, treating the change in the interaction as a small parameter, for all $τ$. We derive the corrections appearing in, a.) the Loschmidt echo for a finite quench duration $τ$, b.) the scaling of the echo following a sudden ($τ\to 0$) quench, and c.) the scaling of the echo after an adiabatic ($τ\to \infty$) quench. We study in detail, the limiting cases of the echo in the early time and infinite time limit, and provide scaling arguments to understand these in a general context. We also show that our perturbative results are in good agreement with the exact numerical ones.

8 pages, 4 figures; updated version; to appear in Phys. Rev. B