  Several superconducting circuit configurations are examined on the existence
of super-radiant phase transitions (SRPTs) in thermal equilibrium. For some
configurations consisting of artificial atoms, whose circuit diagrams are
however not specified, and an LC resonator or a transmission line, we confirm
the absence of SRPTs in the thermal equilibrium following the similar analysis
as the no-go theorem for atomic systems. We also show some other configurations
where the absence of SRPTs cannot be confirmed.
