Perturbative post-quench overlaps in Quantum Field Theory
Statistical Mechanics
2019-09-04 v2 High Energy Physics - Theory
Abstract
In analytic descriptions of quantum quenches, the overlaps between the initial pre-quench state and the eigenstates of the time evolving Hamiltonian are crucial ingredients. We construct perturbative expansions of these overlaps in quantum field theories where either the pre-quench or the post-quench Hamiltonian is integrable. Using the Ising field theory for concrete computations, we give explicit expressions for the overlaps up to second order in the quench size, and verify our results against numerical results obtained using the Truncated Conformal Space Approach. We demonstrate that the expansion using the post-quench basis is very effective, but find some serious limitations for the alternative approach using the pre-quench basis.
Cite
@article{arxiv.1905.05623,
title = {Perturbative post-quench overlaps in Quantum Field Theory},
author = {Kristóf Hódsági and Márton Kormos and Gábor Takács},
journal= {arXiv preprint arXiv:1905.05623},
year = {2019}
}