1306.4992 (P. J. de Visser et al.)

Nonlinear electrodynamics of a superconductor due to the redistribution
of quasiparticles    [PDF]

P. J. de Visser, D. J. Goldie, P. Diener, S. Withington, J. J. A. Baselmans, T. M. Klapwijk

We have measured the electrodynamic response, quality factor and resonant frequency, of a superconducting aluminium resonator as a function of microwave power and temperature. Below 200 mK, both the quality factor and resonant frequency decrease with increasing microwave power. Above 200 mK, the quality factor increases with increasing power, which can neither be explained by an effective temperature, nor by a current dependent superfluid density. The measured microwave power and temperature dependence of both the electrodynamic response and the quasiparticle recombination time is consistently explained by non-equilibrium quasiparticle and phonon distributions due to the absorption of microwave photons.

View original: http://arxiv.org/abs/1306.4992