Two-dimensional lattice gauge theories with superconducting quantum circuits

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D. Marcos, P. Widmer, E. Rico, M. Hafezi, P. Rabl, U.-J. Wiese, P. Zoller Annals of Physics 351, 634-654 (2014)

Despite significant progress and efforts, lattice gauge theories remain to be challenging to be simulated on classical computers. A quantum simulator of U(1) lattice gauge theories can however be implemented with superconducting circuits. This allows, for instance, the investigation of confined and deconfined phases in quantum link models, and of valence bond solid and spin liquid phases in quantum dimer models.

In their work, Marcos and co-workers, show how state-of-the-art superconducting technology allows one to simulate these phenomena in relatively small circuit lattices. By exploiting the strong non-linear couplings between quantized excitations emerging when superconducting qubits are coupled, they show how to engineer gauge invariant Hamiltonians, including ring-exchange and four-body Ising interactions. They also demonstrate that, despite the presence of decoherence and disorder effects, minimal circuit instances suffice to investigate properties such as the dynamics of electric flux strings or signaling confinement in gauge invariant field theories. The experimental realization of these models in larger superconducting circuits could address open questions beyond current computational capability.