Quantum simulation of lattice gauge theories via deterministic duality transformations assisted by measurements

Abstract

Quantum simulation is one of the major applications of quantum devices. In the noisy intermediate-scale quantum era, however, the general quantum simulation is not yet feasible, such as that of lattice gauge theories, which is likely limited due to the violation of the Gauss law constraint and the complexity of the real-time dynamics, especially in the deconfined phase. Inspired by the recent works of S. Ashkenazi and E. Zohar [Phys. Rev. A 105, 022431 (2022)] and of N. Tantivasadakarn, R. Thorngren, A. Vishwanath, and R. Verresen [arXiv: 2112.01519], we propose to simulate dynamics of lattice gauge theories by using the Kramers-Wannier transfomation via cluster-state-like entanglers, mid-circuit measurements and feedforwarded corrections, which altogether is a constant-depth deterministic operation. In our scheme, specifically, we first quantum simulate the time evolution under a corresponding symmetric Hamiltonian from an initial symmetric state, and then apply the Kramers-Wannier procedure. This results in a wave function that has time evolved under the corresponding lattice gauge theory from a corresponding initial, gauged wave function. In the presence of noises in time evolution, the procedure succeeds when we can pair up magnetic monopoles represented by non-trivial measurement outcomes. Further, given a noise-free Kramers-Wannier transformation, the resulting wave function from a noisy time evolution satisfies the Gauss law constraint. We give explicit examples with the low dimensional pure gauge theories and gauge theories coupled to bosonic/fermionic matters such as the Fradkin-Shenker model.