## Superradiant Phase Transition in a Superconducting Circuit in Thermal Equilibrium

We propose a superconducting circuit that shows a superradiant phase transition (SRPT) in thermal equilibrium. The existence of the SRPT is confirmed analytically in the limit of an infinite number of artificial atoms. We also perform a numerical diagonalization of the Hamiltonian with a finite number of atoms and observe an asymptotic behavior approaching the infinite limit as the number of atoms increases. The SRPT can also be interpreted intuitively in a classical analysis.

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__Motoaki Bamba__, Kunihiro Inomata, and Yasunobu Nakamura

*Superradiant Phase Transition in a Superconducting Circuit in Thermal Equilibrium*

Physical Review Letters **117**, 173601 (2016)

arXiv:1605.01124 [quant-ph]