Magic and Wormholes in the Sachdev-Ye-Kitaev Model

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Hauptverfasser: Bettaque, Valérie, Swingle, Brian
Format: Preprint
Veröffentlicht: 2026
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author Bettaque, Valérie
Swingle, Brian
author_facet Bettaque, Valérie
Swingle, Brian
contents Any quantum state is fully specified by the expectation values of a complete set of Hermitian operators. For a system of Majorana fermions, such as the Sachdev-Ye-Kitaev (SYK) model, this set of observables can be taken to be all possible strings of Majorana fermion operators. The expectation values of these fermion strings in a thermal state depend erratically on the microscopic couplings that specify the SYK Hamiltonian, and we study their statistical properties directly in the thermodynamic limit using path integral techniques. When the underlying SYK Hamiltonian is chaotic, we find that these expectation values are well-modeled as real Gaussian random variables with zero mean and a variance that we compute. In contrast, for the integrable variant of SYK, we find that the expectation values are actually non-Gaussian. We then use these results to study measures of magic in the SYK thermal state, including the robustness of magic and the stabilizer Rényi entropy. We also show that our results can be quantitatively reproduced with a dual gravity calculation in the chaotic case at sufficiently low temperature. In this dual gravity model the variance of a given microscopic operator string is related to a wormhole geometry stabilized by a massive particle which is dual to the operator string. Our results thus provide a concrete and quantitative setting in which to study the relationship between randomness, wormholes, and closed universes as well as a holographic dual of quantum magic.
format Preprint
id arxiv_https___arxiv_org_abs_2602_12339
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Magic and Wormholes in the Sachdev-Ye-Kitaev Model
Bettaque, Valérie
Swingle, Brian
High Energy Physics - Theory
Strongly Correlated Electrons
General Relativity and Quantum Cosmology
Quantum Physics
Any quantum state is fully specified by the expectation values of a complete set of Hermitian operators. For a system of Majorana fermions, such as the Sachdev-Ye-Kitaev (SYK) model, this set of observables can be taken to be all possible strings of Majorana fermion operators. The expectation values of these fermion strings in a thermal state depend erratically on the microscopic couplings that specify the SYK Hamiltonian, and we study their statistical properties directly in the thermodynamic limit using path integral techniques. When the underlying SYK Hamiltonian is chaotic, we find that these expectation values are well-modeled as real Gaussian random variables with zero mean and a variance that we compute. In contrast, for the integrable variant of SYK, we find that the expectation values are actually non-Gaussian. We then use these results to study measures of magic in the SYK thermal state, including the robustness of magic and the stabilizer Rényi entropy. We also show that our results can be quantitatively reproduced with a dual gravity calculation in the chaotic case at sufficiently low temperature. In this dual gravity model the variance of a given microscopic operator string is related to a wormhole geometry stabilized by a massive particle which is dual to the operator string. Our results thus provide a concrete and quantitative setting in which to study the relationship between randomness, wormholes, and closed universes as well as a holographic dual of quantum magic.
title Magic and Wormholes in the Sachdev-Ye-Kitaev Model
topic High Energy Physics - Theory
Strongly Correlated Electrons
General Relativity and Quantum Cosmology
Quantum Physics
url https://arxiv.org/abs/2602.12339