Motoaki BAMBA won a Research Award from Research Foundation for Opto-Science and Technology. His research on “Exploring physical systems showing super-radiant phase transitions” was approved as a “Creative research for advancing opto-science and technology”.
Tag Archive: Ultrastrong
Circuit configurations which may or may not show superradiant phase transitions
Several superconducting circuit configurations are examined on the existence of superradiant 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.
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.