Sparsity dependence of Krylov state complexity in the SYK model

We study the Krylov state complexity of the Sachdev-Ye-Kitaev (SYK) model for N ≤ 28 Majorana fermions with q -body fermion interaction with q = 4 , 6, 8 for a range of sparse parameter k that controls the number of remaining terms in the original SYK model after sparsification. The critical value o...

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Bibliographic Details
Published in:Physical review. D Vol. 112; no. 4
Main Authors: Jha, Raghav G., Roy, Ranadeep
Format: Journal Article
Language:English
Published: United States American Physical Society (APS) 21.08.2025
ISSN:2470-0010, 2470-0029, 2470-0029
Online Access:Get full text
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Summary:We study the Krylov state complexity of the Sachdev-Ye-Kitaev (SYK) model for N ≤ 28 Majorana fermions with q -body fermion interaction with q = 4 , 6, 8 for a range of sparse parameter k that controls the number of remaining terms in the original SYK model after sparsification. The critical value of k below which the model ceases to be holographic, denoted k c , has been subject of several recent investigations. Using Krylov complexity as a probe, we find that the peak value of complexity does not change as we increase k beyond k ≥ k min at large temperatures. We argue that this behavior is related to the change in the holographic nature of the Hamiltonian in the sparse SYK-type models such that the model is holographic for all k ≥ k min ≈ k c . Our results provide a novel way to determine k c in SYK-type models.
Bibliography:U.S. Department of Energy
JLAB-THY-24-4131; DOE/OR/23177-7578; arXiv:2407.20569
Office of Science
Co-design Center for Quantum Advantage
AC05-06OR23177; SC0012704
National Quantum Information Science Research Centers
ISSN:2470-0010
2470-0029
2470-0029
DOI:10.1103/qsyk-m3sg