The Structure of Emulations in Classical Spin Models: Modularity and Universality

Fuente: arXiv
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Main Authors: Reinhart, Tobias, Engel, Benjamin, Coves, Gemma De les
Format: Preprint
Published: 2024
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author Reinhart, Tobias
Engel, Benjamin
Coves, Gemma De les
author_facet Reinhart, Tobias
Engel, Benjamin
Coves, Gemma De les
contents The theory of spin models intersects with condensed matter physics, complex systems, graph theory, combinatorial optimization, computational complexity and neural networks. Many ensuing applications rely on the fact that complicated spin models can be transformed to simpler ones. What is the structure of such transformations? Here, we provide a framework to study and construct emulations between spin models. A spin model is a set of spin systems, and emulations are efficiently computable simulations with arbitrary energy cut-off, where a source spin system simulates a target system if, below the cut-off, the target Hamiltonian is encoded in the source Hamiltonian. We prove that emulations preserve important properties, as they induce reductions between computational problems such as computing ground states, approximating partition functions and approximate sampling from Boltzmann distributions. Emulations are modular (they can be added, scaled and composed), and allow for universality, i.e. certain spin models have maximal reach. We prove that a spin model is universal if and only if it is scalable, closed and functional complete. Because the characterization is constructive, it provides a step-by-step guide to construct emulations. We prove that the 2d Ising model with fields is universal, for which we also provide two new crossing gadgets. Finally, we show that simulations can be computed by linear programs. While some ideas of this work are contained in [1], we provide new definitions and theorems. This framework provides a toolbox for applications involving emulations of spin models.
format Preprint
id arxiv_https___arxiv_org_abs_2407_13428
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Structure of Emulations in Classical Spin Models: Modularity and Universality
Reinhart, Tobias
Engel, Benjamin
Coves, Gemma De les
Mathematical Physics
Statistical Mechanics
The theory of spin models intersects with condensed matter physics, complex systems, graph theory, combinatorial optimization, computational complexity and neural networks. Many ensuing applications rely on the fact that complicated spin models can be transformed to simpler ones. What is the structure of such transformations? Here, we provide a framework to study and construct emulations between spin models. A spin model is a set of spin systems, and emulations are efficiently computable simulations with arbitrary energy cut-off, where a source spin system simulates a target system if, below the cut-off, the target Hamiltonian is encoded in the source Hamiltonian. We prove that emulations preserve important properties, as they induce reductions between computational problems such as computing ground states, approximating partition functions and approximate sampling from Boltzmann distributions. Emulations are modular (they can be added, scaled and composed), and allow for universality, i.e. certain spin models have maximal reach. We prove that a spin model is universal if and only if it is scalable, closed and functional complete. Because the characterization is constructive, it provides a step-by-step guide to construct emulations. We prove that the 2d Ising model with fields is universal, for which we also provide two new crossing gadgets. Finally, we show that simulations can be computed by linear programs. While some ideas of this work are contained in [1], we provide new definitions and theorems. This framework provides a toolbox for applications involving emulations of spin models.
title The Structure of Emulations in Classical Spin Models: Modularity and Universality
topic Mathematical Physics
Statistical Mechanics
url https://arxiv.org/abs/2407.13428