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arXiv · 2203.14035

Locating quantum critical points with shallow quantum circuits

Zhi-Quan Shi·Fang-Gang Duan·Dan-Bo Zhang
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Abstract

Quantum critical point is one key concept for studying many-body physics but its investigation may be resource-demanding even for a quantum computer due to the intrinsic complexity. In this paper, we propose an approach based on variational quantum eigensolver(VQE), dubbed as Delta-VQE, for locating the quantum critical point using only shallow quantum circuits. With Delta-VQE, the critical point can be identified as a most confusing point, quantified as zero difference between two variational energies that use two representative reference states of distinct phases of matter. Remarkably, the signature of a critical point as a minimal point can be sharper while using shallower quantum circuits. We test the algorithm for different quantum systems and demonstrate the usefulness of Delta-VQE. The scheme suggests a new avenue for investigating quantum phases of matter on near-term quantum devices with limited quantum resources.

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Zhi-Quan Shi, Fang-Gang Duan, Dan-Bo Zhang. 2022-03-26. Locating quantum critical points with shallow quantum circuits. https://doi.org/10.1016/j.physleta.2023.128683

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