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arXiv · 2607.04669

Estimation of a sparse multi-qubit Hamiltonian via compressed sensing

Juntao Tu·Yuanlong Wang·Shuming Cheng·Shuixin Xiao·Zhibo Hou
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Abstract

Hamiltonian estimation is an effective approach in studying the structure and dynamical evolution of quantum systems. The difficulty in estimating the Hamiltonian is that an $N$-qubit Hamiltonian has $4^N-1$ unknown parameters, requiring exponentially many equations for information extraction. In this paper we develop a method based on compressed sensing to estimate the Hamiltonian of a multi-qubit system. We identify a problem where as $N$ increases, the common sufficient condition (Restricted Isometry Property) for compressed sensing often fails, obstructing the application of compressed sensing in ($N\geq 3$)-qubit Hamiltonian estimation. To solve this problem, we propose a ``scale transformation" technique to restore RIP and ensure a compressive estimation of a $k$-sparse Hamiltonian using only $O(k\log(4^N/k))$ equations. In the numerical examples, we estimate the Hamiltonians of two 6- and 30-qubit systems, demonstrating the effectiveness of the method.

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Juntao Tu, Yuanlong Wang, Shuming Cheng, Shuixin Xiao, Zhibo Hou. 2026-07-06. Estimation of a sparse multi-qubit Hamiltonian via compressed sensing. https://arxiv.org/abs/2607.04669

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