Fast Preparation of Critical Ground States Using Superluminal Fronts

Kartiek Agarwal, R. N. Bhatt, and S. L. Sondhi
Phys. Rev. Lett. 120, 210604 – Published 22 May 2018
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Abstract

We propose a spatiotemporal quench protocol that allows for the fast preparation of ground states of gapless models with Lorentz invariance. Assuming the system initially resides in the ground state of a corresponding massive model, we show that a superluminally moving “front” that locally quenches the mass, leaves behind it (in space) a state arbitrarily close to the ground state of the gapless model. Importantly, our protocol takes time O(L) to produce the ground state of a system of size Ld (d spatial dimensions), while a fully adiabatic protocol requires time O(L2) to produce a state with exponential accuracy in L. The physics of the dynamical problem can be understood in terms of relativistic rarefaction of excitations generated by the mass front. We provide proof of concept by solving the proposed quench exactly for a system of free bosons in arbitrary dimensions, and for free fermions in d=1. We discuss the role of interactions and UV effects on the free-theory idealization, before numerically illustrating the usefulness of the approach via simulations on the quantum Heisenberg spin chain.

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  • Received 16 November 2017
  • Revised 19 February 2018

DOI:https://doi.org/10.1103/PhysRevLett.120.210604

© 2018 American Physical Society

Physics Subject Headings (PhySH)

Statistical Physics & ThermodynamicsQuantum Information, Science & TechnologyCondensed Matter, Materials & Applied PhysicsAtomic, Molecular & Optical

Authors & Affiliations

Kartiek Agarwal1,*, R. N. Bhatt1, and S. L. Sondhi2

  • 1Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08540, USA
  • 2Department of Physics, Princeton University, Princeton, New Jersey 08544, USA

  • *kagarwal@princeton.edu

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Issue

Vol. 120, Iss. 21 — 25 May 2018

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