Characterization of an entangled system of two superconducting qubits using a multiplexed capacitance measurement
Matthew D. Shaw, Justin F. Schneiderman, Juan Bueno, B. S. Palmer, Per Delsing, P. M. Echternach · Physical Review B · 2009
We characterize a pair of Cooper-pair boxes coupled with a fixed capacitor using spectroscopy and measurements of the ground-state quantum capacitance. We use the extracted parameters to estimate the concurrence or degree of entanglement between the two qubits. We also present a thorough demonstration of a multiplexed quantum capacitance measurement technique, which is in principle scalable to a large array of superconducting qubits.