Probing mixed-state phases on a quantum computer via Renyi correlators and variational decoding
Abstract
Recent advances have defined nontrivial phases of matter in open quantum systems, such as many-body quantum states subject to environmental noise. In this work, we experimentally probe and characterize mixed-state phases on Quantinuum's H1 quantum computer using two measures: Renyi correlators and the coding performance of a quantum error-correcting code associated with the phase. As a concrete example, we probe the low-energy states of the critical transverse field Ising model under different dephasing noise channels. First, we employ shadow tomography to observe a newly proposed Renyi correlator in two distinct phases: one exhibiting power-law decay and the other long-ranged. Second, we investigate the decoding fidelity of the associated quantum error-correcting code using a variational quantum circuit, and we find that a shallow circuit is sufficient to distinguish the above-mentioned two mixed-state phases through the decoding performance quantified by entanglement fidelity. Our work is a proof of concept for the quantum simulation and characterization of mixed-state phases.
Cite
@article{arxiv.2505.02900,
title = {Probing mixed-state phases on a quantum computer via Renyi correlators and variational decoding},
author = {Yuxuan Zhang and Timothy H. Hsieh and Yong Baek Kim and Yijian Zou},
journal= {arXiv preprint arXiv:2505.02900},
year = {2025}
}