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Signaling and scrambling with strongly long-range interactions

TitleSignaling and scrambling with strongly long-range interactions
Publication TypeJournal Article
Year of Publication2020
AuthorsA. Y. Guo, M. C. Tran, A. M. Childs, , and Z-X. Gong
JournalPhys. Rev. A
Volume102
Pagination010401
Date PublishedJUL 8
Type of ArticleArticle
ISSN1050-2947
Abstract

Strongly long-range interacting quantum systems-those with interactions decaying as a power law 1/r(alpha) in the distance r on a D-dimensional lattice for alpha <= D-have received significant interest in recent years. They are present in leading experimental platforms for quantum computation and simulation, as well as in theoretical models of quantum-information scrambling and fast entanglement creation. Since no notion of locality is expected in such systems, a general understanding of their dynamics is lacking. In a step towards rectifying this problem, we prove two Lieb-Robinson-type bounds that constrain the time for signaling and scrambling in strongly long-range interacting systems, for which no tight bounds were previously known. Our first bound applies to systems mappable to free-particle Hamiltonians with long-range hopping, and is saturable for alpha <= D/2. Our second bound pertains to generic long-range interacting spin Hamiltonians and gives a tight lower bound for the signaling time to extensive subsets of the system for all alpha < D. This many-site signaling time lower bounds the scrambling time in strongly long-range interacting systems.

DOI10.1103/PhysRevA.102.010401