Introduction of a DC Bias into a High-Q Superconducting Microwave Cavity

The circuit quantum electrodynamics (QED) architecture has been demonstrated to allow study of cavity QED physics in a high-Q on-chip microwave cavity[1]. Here we develop a technique to apply a DC current or voltage bias to nanostructures embedded in the microwave cavity without significantly degrading the Q at high frequencies. Experimental results show good agreement with theoretical predictions. New highly non-linear fully quantum mechanical devices can be developed by embedding Josephson junction devices such as single electron transistors (SETs) in the high-Q microwave cavity. The interplay between the SET and the microwave cavity offers an interesting system for studying nonlinear quantum dynamics and the quantum-to-classical transition. Recent experimental results will be discussed. \\[4pt] [1] A. Wallraff et al, Nature, 431, 162 (2004).