Quantum phases in circuit QED with a superconducting qubit array

Understand

Circuit QED on a chip has become a powerful platform for simulating complex many-body physics.

• In this report, we realize a Dicke-Ising model with an antiferromagnetic nearest-neighbor spin-spin interaction in circuit QED with a superconducting qubit array.
• We show that this system exhibits a competition between the collective spin-photon interaction and the antiferromagnetic nearest-neighbor spin-spin interaction, and then predict four quantum phases, including: a paramagnetic normal phase, an antiferromagnetic normal phase, a paramagnetic superradiant phase, and an antiferromagnetic superradiant phase.
• The antiferromagnetic normal phase and the antiferromagnetic superradiant phase are new phases in many-body quantum optics.