Measurement-based quantum simulation of Abelian lattice gauge theories

Abstract: The digital quantum simulation of lattice gauge theories is expected to become a major application of quantum computers. Measurement-based quantum computation is a widely studied competitor of the standard circuit-based approach. We formulate a measurement-based scheme to perform the quantum simulation of Abelian lattice gauge theories in general dimensions. The scheme uses an entangled resource state that is tailored for the purpose of gauge theory simulation and reflects the spacetime structure of the simulated theory. Sequential single-qubit measurements with the bases adapted according to the former measurement outcomes induce a deterministic Hamiltonian quantum simulation of the gauge theory on the boundary. We treat as our main example the $\mathbb{Z}_2$ lattice gauge theory in $2+1$ dimensions, simulated on a 3-dimensional cluster state. Then we generalize the simulation scheme to Wegner's lattice models that involve higher-form Abelian gauge fields. The resource state has a symmetry-protected topological order with respect to generalized global symmetries that are related to the symmetries of the simulated gauge theories. We also propose a method to simulate the imaginary-time evolution with two-qubit measurements and post-selections.