[19p-C207-1~17] 11.4 Analog applications and their related technologies

[19p-C207-4] Nonlinear electrical conductivity of quasiparticles in a superconducting resonator

〇Takashi Noguchi^1,2, Matthias Kroug², Satoru Mima¹, Chiko Otani¹ (1.RIKEN, 2.NAOJ)

Keywords:superconductor, microwave resonator, nonlinear electrical conductivity

In a superconducting resonator using Nb or Al thin film, the internal Q value Q_i depends on the readout microwave power and increases as the power increases. On the other hand, at a sufficiently low temperature, the resonance frequency f_r of these superconducting resonators do not depend on the readout microwave power. Here, we analyzed that the unique behavior of those resonance characteristics was due to the nonlinearity of the electrical conductivity of the residual quasiparticle to the microwave electric field.