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arXiv · 2506.05323

Non-Perturbative Topological Gadgets for Many-Body Coupling

David Headley·Nicholas Chancellor
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Abstract

Continuous-time quantum hardware implementations generally lack the native capability to implement high-order terms that would facilitate efficient compilation of quantum algorithms. This limitation has, in part, motivated the development of perturbative gadgets -- multi-qubit constructions used to effect a desired Hamiltonian using engineered low-energy subspaces of a larger system constructed using simpler, usually two-body, primitives. In this work, we demonstrate how a class of non-perturbative gadgets can produce high-order multi-body interactions by taking advantage of the odd-even properties of topological defect subspaces. The simplest example is based on domain-wall defects forming an effective Ising spin-chain based on three-body coupling with linear connectivity, alongside three-, or five-body driving terms depending on the intended use. Although this will be the main focus of the paper due to conceptual simplicity, there exist systems constructed with only two-body couplings where the boundaries determine whether there are an odd or even number of defects, namely ice-like systems which may yield more complex gadget-like constructions.

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David Headley, Nicholas Chancellor. 2025-06-05. Non-Perturbative Topological Gadgets for Many-Body Coupling. https://doi.org/10.1088/2058-9565%2Fae6fe2

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