Bounds on the ground state energy of quantum $p$-spin Hamiltonians

Fuente: arXiv
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Autores principales: Anschuetz, Eric R., Gamarnik, David, Kiani, Bobak T.
Formato: Preprint
Publicado: 2024
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author Anschuetz, Eric R.
Gamarnik, David
Kiani, Bobak T.
author_facet Anschuetz, Eric R.
Gamarnik, David
Kiani, Bobak T.
contents We consider the problem of estimating the ground state energy of quantum $p$-local spin glass random Hamiltonians, the quantum analogues of widely studied classical spin glass models. Our main result shows that the maximum energy achievable by product states has a well-defined limit (for even $p$) as $n\to\infty$ and is $E_{\text{product}}^\ast=\sqrt{2 \log p}$ in the limit of large $p$. This value is interpreted as the maximal energy of a much simpler so-called Random Energy Model, widely studied in the setting of classical spin glasses. The proof of the limit existing follows from an extension of Fekete's Lemma after we demonstrate near super-additivity of the (normalized) quenched free energy. The proof of the value follows from a second moment method on the number of states achieving a given energy when restricting to an $ε$-net of product states. Furthermore, we relate the maximal energy achieved over all states to a $p$-dependent constant $γ\left(p\right)$, which is defined by the degree of violation of a certain asymptotic independence ansatz over graph matchings. We show that the maximal energy achieved by all states $E^\ast\left(p\right)$ in the limit of large $n$ is at most $\sqrt{γ\left(p\right)}E_{\text{product}}^\ast$. We also prove using Lindeberg's interpolation method that the limiting $E^\ast\left(p\right)$ is robust with respect to the choice of the randomness and, for instance, also applies to the case of sparse random Hamiltonians. This robustness in the randomness extends to a wide range of random Hamiltonian models including SYK and random quantum max-cut.
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id arxiv_https___arxiv_org_abs_2404_07231
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Bounds on the ground state energy of quantum $p$-spin Hamiltonians
Anschuetz, Eric R.
Gamarnik, David
Kiani, Bobak T.
Quantum Physics
We consider the problem of estimating the ground state energy of quantum $p$-local spin glass random Hamiltonians, the quantum analogues of widely studied classical spin glass models. Our main result shows that the maximum energy achievable by product states has a well-defined limit (for even $p$) as $n\to\infty$ and is $E_{\text{product}}^\ast=\sqrt{2 \log p}$ in the limit of large $p$. This value is interpreted as the maximal energy of a much simpler so-called Random Energy Model, widely studied in the setting of classical spin glasses. The proof of the limit existing follows from an extension of Fekete's Lemma after we demonstrate near super-additivity of the (normalized) quenched free energy. The proof of the value follows from a second moment method on the number of states achieving a given energy when restricting to an $ε$-net of product states. Furthermore, we relate the maximal energy achieved over all states to a $p$-dependent constant $γ\left(p\right)$, which is defined by the degree of violation of a certain asymptotic independence ansatz over graph matchings. We show that the maximal energy achieved by all states $E^\ast\left(p\right)$ in the limit of large $n$ is at most $\sqrt{γ\left(p\right)}E_{\text{product}}^\ast$. We also prove using Lindeberg's interpolation method that the limiting $E^\ast\left(p\right)$ is robust with respect to the choice of the randomness and, for instance, also applies to the case of sparse random Hamiltonians. This robustness in the randomness extends to a wide range of random Hamiltonian models including SYK and random quantum max-cut.
title Bounds on the ground state energy of quantum $p$-spin Hamiltonians
topic Quantum Physics
url https://arxiv.org/abs/2404.07231