Description
Lattice models can be employed to understand a wide range of phenomena, from elementary particles in high energy physics to effective descriptions of many-body interactions in materials. In these models, studying the emergent phases and their dynamical properties can be extremely challenging as it requires solving many-body problems that are generally beyond the perturbative limit.Using a 2D lattice of superconducting qubits, we study dynamics of local excitations in a $\mathbb{Z}_2$ lattice gauge theory (LGT). Implementing a simple variational ansatz allows us to design circuits to prepare low-energy quantum states with large overlap with the groundstate of the model via continuous variation of a single parameter. Particles can then be created using local gate operations and their dynamics simulated via a discretized time evolution. As the effective magnetic field strength is increased, measurements show clear signatures of transitioning from a deconfined to a confined phase. In the confined phase, tuning the effective magnetic field induces tension in the string connecting the charge excitations, which we observe with two-time correlation functions. Our LGT implementation on a quantum processor highlights a novel approach for studying dynamics of interacting elementary excitations.
