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arXiv · 2609.05838

High-Resolution Dynamical Eigenspectroscopy via Variational Trotter Compression on a Superconducting Qubit Processor

Liyang Sui·Xingrui Liu·Yufan Li·Sainan Huai·Zhiwen Zong·Kunliang Bu·Xiaopei Yang·Wenyan Jin·Bowen Chen·Xutao Zhang·Jianlan Wu·Shengyu Zhang·Yi Yin
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Abstract

The pursuit of high-resolution eigenspectroscopy on noisy intermediate-scale quantum devices is often hindered by the trade-off between circuit depth and coherence time. In this work, we introduce and experimentally demonstrate a dynamical eigenspectroscopy protocol that extracts fine-grained energy structures from time-dependent survival amplitudes. To overcome the finite coherence window of current superconducting processors, we employ Variational Trotter Compression (VTC) as a practical means to extend the duration of high-fidelity unitary evolution. Using a multi-connected 9-qubit superconducting processor, we reconstruct the time-domain autocorrelation signal via quantum state tomography for the H2 molecule at different bond lengths and for the Fermi-Hubbard model across different correlation regimes. Through multi-frequency fitting and Fourier analysis, the extracted eigenenergies agree with the exact-diagonalization values to within 2x10^-3, including the near-degenerate levels in the strongly interacting regime. Our results establish experimental dynamical spectroscopy as a robust and generalizable framework for simulating both quantum chemistry and strongly correlated lattice systems, bridging weak- and strong-coupling regimes on near-term quantum hardware.

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Liyang Sui, Xingrui Liu, Yufan Li, Sainan Huai, Zhiwen Zong, Kunliang Bu, Xiaopei Yang, Wenyan Jin, Bowen Chen, Xutao Zhang, Jianlan Wu, Shengyu Zhang, Yi Yin. 2026-09-05. High-Resolution Dynamical Eigenspectroscopy via Variational Trotter Compression on a Superconducting Qubit Processor. https://arxiv.org/abs/2609.05838

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