Loops and strings in a superconducting lattice gauge simulator

  1. G.K. Brennen,
  2. G. Pupillo,
  3. E. Rico,
  4. T.M. Stace,
  5. and D. Vodola
We propose a quantum simulation of electromagnetism in (2+1) dimensions using an array of superconducting fluxonium devices. The encoding is in the integer (S=1) representation of the
quantum link model formulation of compact U(1) lattice gauge theory. We show how to engineer the Gauss constraint via an ancilla mediated gadget construction and how to tune between the strongly coupled and intermediately coupled regimes. The witnesses to the existence of the predicted confining phase of the model are provided by non-local order parameters from Wilson loops and disorder parameters from ‚t Hooft strings and we show how to measure these operators non-destructively via dispersive coupling of the fluxonium islands to a microwave cavity mode. Evidence for existence of the confined phase in the ground state of the simulation Hamiltonian is found by DMRG calculations on a ladder geometry.