1.
Phys Rev Lett
; 95(20): 206806, 2005 Nov 11.
Article
in English
| MEDLINE
| ID: mdl-16384085
ABSTRACT
The effective capacitance has been measured in the split Cooper-pair box (CPB) over its phase-gate bias plane. Our low-frequency reactive measurement scheme allows us to probe purely the capacitive susceptibility due to the CPB band structure. The data are quantitatively explained using parameters determined independently by spectroscopic means. In addition, we show in practice that the method offers an efficient way to do nondemolition readout of the CPB quantum state.