Native Three-Body Interactions in a Superconducting Lattice Gauge Quantum Simulator

TL;DR

This paper demonstrates a novel three-qubit interaction in a superconducting quantum simulator that enforces gauge invariance, enabling the simulation of lattice gauge theories with local constraints.

Contribution

It introduces and experimentally implements a parametric three-qubit interaction to realize gauge-invariant dynamics in a superconducting circuit.

Findings

Successfully demonstrated a minimal U(1) gauge model respecting Gauss's law

Implemented a three-qubit interaction that enforces local gauge constraints

Laid groundwork for simulating lattice gauge theories on superconducting platforms

Abstract

While universal quantum computers remain under development, analog quantum simulators offer a powerful alternative for understanding complex systems in condensed matter, chemistry, and high-energy physics. One compelling application is the characterization of real-time lattice gauge theories (LGTs). LGTs are nonperturbative tools, utilizing discretized spacetime to describe gauge-invariant models. They hold immense potential for understanding fundamental physics but require enforcing local constraints analogous to electromagnetism's Gauss's Law. These constraints, which arise from gauge symmetries and dictate the form of the interaction between matter and gauge fields, are a significant challenge for simulators to enforce. Implementing these constraints at the hardware level in analog simulations is crucial. This requires realizing multibody interactions between matter and gauge-field elements, enabling them to evolve together while suppressing unwanted two-body interactions that violate the gauge symmetry. In this paper, we propose and implement a novel parametrically activated three-qubit interaction within a circuit quantum electrodynamics architecture. We experimentally demonstrate a minimal $U(1)$ spin-1/2 model with a time evolution that intrinsically satisfies Gauss's law in the system. This design serves as the foundational block for simulating LGTs on a superconducting photonic lattice.