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QI: Fachverband Quanteninformation
QI 27: Quantum Simulation II
QI 27.3: Vortrag
Donnerstag, 21. März 2024, 15:30–15:45, HFT-FT 101
Robust Experimental Signatures of Phase Transitions in the Variational Quantum Eigensolver — •Kevin Lively1, Tim Bode2, Jochen Szangolies1, Jian-Xin Zhu3, and Benedikt Fauseweh4 — 1Deutsches Zentrum für Luft- und Raumfahrt — 2Forschungszentrum Jülich — 3Los Alamos National Laboratory — 4Technische Universität Dortmund
The Variational Quantum Eigensolver (VQE) is widely considered to be a promising candidate for a quantum-classical algorithm which could achieve near-term quantum advantage. However, current levels of hardware noise can require extensive application of error mitigation techniques in order for the results of calculations to be meaningful. In this work we use several IBM devices to explore a finite size spin model with multiple 'phase-like' regions characterized by distinct ground state configurations. Using pre-optimized VQE solutions, we demonstrate that in contrast to calculating the energy, where zero noise extrapolation is required in order to obtain qualitatively accurate results, calculation of the two site spin correlation functions and fidelity susceptibility yields accurate behavior across multiple regions. Taken together, these two sets of observables could be used to identify level crossing in VQE solutions in a simple and noise robust manner, with potential near-term application to identifying avoided crossings and non-adiabatic conical intersections in electronic structure calculations.
Keywords: Variational Quantum Eigensolver; Error Mitigation; Fidelity Susceptibility; Quantum Computing; Phase Transition