Published October 22, 2021 | Version Accepted Version + Published + Supplemental Material
Journal Article Open

Quantum Variational Learning of the Entanglement Hamiltonian

  • 1. ROR icon Institute for Quantum Optics and Quantum Information Innsbruck
  • 2. ROR icon Universität Innsbruck
  • 3. ROR icon University of Colorado Boulder
  • 4. ROR icon Joint Institute for Laboratory Astrophysics
  • 5. ROR icon California Institute of Technology
  • 6. ROR icon Laboratoire de Physique et Modélisation des Milieux Condensés
  • 7. ROR icon International Centre for Theoretical Physics
  • 8. ROR icon International School for Advanced Studies

Abstract

Learning the structure of the entanglement Hamiltonian (EH) is central to characterizing quantum many-body states in analog quantum simulation. We describe a protocol where spatial deformations of the many-body Hamiltonian, physically realized on the quantum device, serve as an efficient variational ansatz for a local EH. Optimal variational parameters are determined in a feedback loop, involving quench dynamics with the deformed Hamiltonian as a quantum processing step, and classical optimization. We simulate the protocol for the ground state of Fermi-Hubbard models in quasi-1D geometries, finding excellent agreement of the EH with Bisognano-Wichmann predictions. Subsequent on-device spectroscopy enables a direct measurement of the entanglement spectrum, which we illustrate for a Fermi Hubbard model in a topological phase.

Additional Information

© 2021 American Physical Society. Received 12 May 2021; revised 20 August 2021; accepted 1 September 2021; published 22 October 2021. We thank L. K. Joshi, R. Kaubrügger, J. Carrasco, J. Yu, and B. Kraus for valuable discussions. We thank Ana Maria Rey and Murray Holland for a careful reading of the manuscript. We acknowledge funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 817482 (Pasquans) and No. 731473 (QuantERA via QT-FLAG). Furthermore, this work was supported by the Simons Collaboration on Ultra-Quantum Matter, which is a grant from the Simons Foundation (651440, P. Z.), and LASCEM by AFOSR No. 64896-PH-QC. M. D. is partly supported by the ERC under Grant No. 758329 (AGEnTh). A. E. acknowledges funding by the German National Academy of Sciences Leopoldina under the Grant No. LPDS 2021-02. B. V. acknowledges funding from the Austrian Science Foundation (FWF, P 32597 N), and the French National Research Agency (ANR-20-CE47-0005, JCJC project QRand). The computational results presented here have been achieved (in part) using the LEO HPC infrastructure of the University of Innsbruck.

Attached Files

Published - PhysRevLett.127.170501.pdf

Accepted Version - 2105.04317.pdf

Supplemental Material - SM.pdf

Files

2105.04317.pdf

Files (5.1 MB)

Name Size
md5:df73cf627d40d7d7f2bbae4796b3dfd5
2.1 MB Preview Download
md5:93ea67dcf4b8dc1628838853fac2b8b5
1.0 MB Preview Download
md5:435177823ead8103aa7ba82f247fb40f
2.0 MB Preview Download

Additional details

Identifiers

Eprint ID
111791
Resolver ID
CaltechAUTHORS:20211108-205323673

Related works

Funding

European Research Council (ERC)
817482
European Research Council (ERC)
731473
Simons Foundation
651440
Air Force Office of Scientific Research (AFOSR)
64896-PH-QC
European Research Council (ERC)
758329
Deutsche Akademie der Naturforscher Leopoldina
LPDS 2021-02
FWF Der Wissenschaftsfonds
P 32597 N
Agence Nationale pour la Recherche (ANR)
ANR-20-CE47-0005

Dates

Created
2021-11-08
Created from EPrint's datestamp field
Updated
2021-11-08
Created from EPrint's last_modified field