Suppressing defect production during passage through a quantum critical point

Abstract

We show that a closed quantum system driven through a quantum critical point with two rates $ω_1$ (which controls its proximity to the quantum critical point) and $ω_2$ (which controls the dispersion of the low-energy quasiparticles at the critical point) exhibits novel scaling laws for defect density $n$ and residual energy $Q$. We demonstrate suppression of both $n$ and $Q$ with increasing $ω_2$ leading to an alternate route to achieving near-adiabaticity in a finite time for a quantum system during its passage through a critical point. We provide an exact solution for such dynamics with linear drive protocols applied to a class of integrable models, supplement this solution with scaling arguments applicable to generic many-body Hamiltonians, and discuss specific models and experimental systems where our theory may be tested.

4.5 pages, 3 figures + Supplementary information