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arXiv · 2111.13080

Accessing ground state and excited states energies in many-body system after symmetry restoration using quantum computers

E. A. Ruiz Guzman·D. Lacroix
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Abstract

We explore the possibility to perform symmetry restoration with the variation after projection technique on a quantum computer followed by additional post-processing. The final goal is to develop configuration interaction techniques based on many-body trial states pre-optimized on a quantum computer. We show how the projection method used for symmetry restoration can prepare optimized states that could then be employed as initial states for quantum or hybrid quantum-classical algorithms. We use the quantum phase estimation and quantum Krylov approaches for the post-processing. The latter method combined with the quantum variation after projection (Q-VAP) leads to very fast convergence towards the ground-state energy. The possibility to access excited states energies is also discussed. Illustrations of the different techniques are made using the pairing hamiltonian.

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E. A. Ruiz Guzman, D. Lacroix. 2021-11-25. Accessing ground state and excited states energies in many-body system after symmetry restoration using quantum computers. https://doi.org/10.1103/physrevc.105.024324

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