Losses in coplanar waveguide resonators at millikelvin temperatures

摘要

We study the loss rate for a set of u0001/2 coplanar waveguide resonators at millikelvin temperaturesnu000120–900 mKu0002 and different applied powers u00013·10−19–10−12 Wu0002. The loss rate becomes powernindependent below a critical power. For a fixed power, the loss rate increases significantly withndecreasing temperature. We show that this behavior can be caused by two-level systems in thensurrounding dielectric materials. Interestingly, the influence of the two-level systems is of the samenorder of magnitude for the different material combinations. That leads to the assumption that thennature of these two-level systems is material independent.