A scalable realization of local U(1) gauge invariance in cold atomic mixtures

Abstract

In the fundamental laws of physics, gauge fields mediate the interaction between charged particles. An example is quantum electrodynamics – the theory of electrons interacting with the electromagnetic field – based on $U(1)$ gauge symmetry. Solving such gauge theories is in general a hard problem for classical computational techniques. While quantum computers suggest a way forward, it is difficult to build large-scale digital quantum devices required for complex simulations. Here, we propose a fully scalable analog quantum simulator of a $U(1)$ gauge theory in one spatial dimension. To engineer the local gauge symmetry, we employ inter-species spin-changing collisions in an atomic mixture. We demonstrate the experimental realization of the elementary building block as a key step towards a platform for large-scale quantum simulations of continuous gauge theories.