Quench dynamics of the Schwinger model via variational quantum algorithms

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Abstract

We investigate the real-time dynamics of the $(1 + 1)$-dimensional $U(1)$ gauge theory known as the Schwinger model via variational quantum algorithms. Specifically, we simulate quench dynamics in the presence of an external electric field. First, we use a variational quantum eigensolver to obtain the ground state of the system in the absence of an external field. With this as the initial state, we perform real-time evolution under an external field via a fixed-depth, parameterized circuit whose parameters are updated using McLachlan’s variational principle. We use the same ansatz for initial-state preparation and time evolution, by which we are able to reduce the overall circuit depth. We test our method with a classical simulator and confirm that the results agree well with exact diagonalization.

Citation

Nagano, L., Bapat, A., & Bauer, C. W. (2023). “Quench dynamics of the Schwinger model via variational quantum algorithms”. Physical Review D, 108(3), 034501.

@article{nagano2023quench,
  title={Quench dynamics of the Schwinger model via variational quantum algorithms},
  author={Nagano, Lento and Bapat, Aniruddha and Bauer, Christian W},
  journal={Physical Review D},
  volume={108},
  number={3},
  pages={034501},
  year={2023},
  publisher={APS}
}