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Collisions of False-Vacuum Bubble Walls in a Quantum Spin Chain

Milsted, Ashley and Liu, Junyu and Preskill, John and Vidal, Guifre (2022) Collisions of False-Vacuum Bubble Walls in a Quantum Spin Chain. PRX Quantum, 3 (2). Art. No. 020316. ISSN 2691-3399. doi:10.1103/PRXQuantum.3.020316.

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We simulate, using nonperturbative methods, the real-time dynamics of small bubbles of “false vacuum” in a quantum spin chain near criticality, where the low-energy physics is described by a relativistic (1+1)-dimensional quantum field theory. We consider bubbles whose walls are kink and antikink quasiparticle excitations, so that wall collisions are kink-antikink scattering events. To construct these bubbles in the presence of strong correlations, we extend a recently proposed matrix product state (MPS) ansatz for quasiparticle wavepackets. We simulate dynamics within a window of about 1000 spins embedded in an infinite chain at energies of up to about 5 times the mass gap. By choosing the wavepacket width and the bubble size appropriately, we avoid strong lattice effects and observe relativistic kink-antikink collisions. We use the MPS quasiparticle ansatz to detect scattering outcomes. (i) In the Ising model, with transverse and longitudinal fields, we do not observe particle production despite nonintegrability (supporting recent observations of nonthermalizing states in this model). (ii) Switching on an additional interaction, we see production of confined and unconfined particle pairs. We characterize the amount of entanglement generated as a function of energy and time and conclude that our classical simulation methods will ultimately fail as these increase. We anticipate that kink-antikink scattering in 1+1 dimensions will be an instructive benchmark problem for future quantum computers and analog quantum simulators.

Item Type:Article
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URLURL TypeDescription Paper
Milsted, Ashley0000-0002-1498-6654
Liu, Junyu0000-0003-1669-8039
Preskill, John0000-0002-2421-4762
Additional Information:© 2022 Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Received 10 March 2021; revised 5 January 2022; accepted 28 March 2022; published 22 April 2022. We thank Alex Buser, Marcela Carena, Cliff Cheung, Natalie Klco, Ying-Ying Li, Spiros Michalakis, Nicola Pancotti, Burak Şahinoğlu, Martin Savage, and Eugene Tang for useful discussions and comments. This material is based upon work supported in part by the U.S. Department of Energy Office of Science, Office of Advanced Scientific Computing Research, (Grants No. DE-NA0003525 and No. DE-SC0020290), and the Office of High Energy Physics (Grants No. DE-ACO2-07CH11359 and No. DE-SC0018407). A.M., J.L., and J.P. also acknowledge funding provided by the Institute for Quantum Information and Matter, a NSF Physics Frontiers Center (NSF Grant No. PHY-1733907), the Simons Foundation It from Qubit Collaboration, and the Air Force Office of Scientific Research (Grant No. FA9550-19-1-0360). G.V. acknowledges support as a CIFAR Fellow in the Quantum Information Science Program. Sandbox is a team within the Alphabet family of companies, which includes Google, Verily, Waymo, X, and others. Research at Perimeter Institute is supported in part by the Government of Canada through the Department of Innovation, Science and Economic Development Canada and by the Province of Ontario through the Ministry of Colleges and Universities. Some of the computations presented here were conducted on the Caltech High Performance Cluster, partially supported by a grant from the Gordon and Betty Moore Foundation.
Group:Walter Burke Institute for Theoretical Physics, Institute for Quantum Information and Matter, AWS Center for Quantum Computing
Funding AgencyGrant Number
Department of Energy (DOE)DE-NA0003525
Department of Energy (DOE)DE-SC0020290
Department of Energy (DOE)DE-ACO2-07CH11359
Department of Energy (DOE)DE-SC0018407
Institute for Quantum Information and Matter (IQIM)UNSPECIFIED
Simons FoundationUNSPECIFIED
Air Force Office of Scientific Research (AFOSR)FA9550-19-1-0360
Canadian Institute for Advanced Research (CIFAR)UNSPECIFIED
Department of Innovation, Science and Economic Development (Canada)UNSPECIFIED
Ontario Ministry of Colleges and UniversitiesUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
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Issue or Number:2
Record Number:CaltechAUTHORS:20210512-104051553
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:109100
Deposited By: George Porter
Deposited On:12 May 2021 19:20
Last Modified:01 Jun 2022 17:00

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