3-Qubit parametric interaction as a tool for quantum simulation

Until universal quantum computers become capable of simulating complicated quantum systems, analog quantum simulators offer the potential to take significant steps in tackling numerous classically intractable problems in areas such as condensed matter physics, chemistry, and high-energy physics. An important class of these simulations is lattice gauge theories (LGTs). LGT is a framework to study gauge theories in discretized space-time, often employed when perturbative techniques fail. The eponymous gauge symmetries present in these theories lead to conservation laws, generalizations of Gauss's Law in electrodynamics, that relate the configuration of "matter" sites to the configuration of gauge fields. Any simulation of a gauge theory must ultimately reproduce these conservation laws, with one strategy in analog simulation being to build them in at the hardware level. This strategy requires having many-body interactions between the elements representing the matter and gauge fields, such that their configurations can evolve simultaneously. At that same time, we must suppress standard two-body interactions that, in general, break the conservation laws. In this talk, we propose and implement a parametrically activated 3-qubit interaction in a circuit QED architecture, as the simplest building block for simulating LGTs in a superconducting photonic lattice. We will discuss the device design and demonstrate the experimental realization of the 3-qubit interaction.