Superconducting phase qubits

Experimental progress is reviewed for superconducting phase qubit research at the University of California, Santa Barbara. The phase qubit has a potential advantage of scalability, based on the low impedance of the device and the ability to microfabricate complex “quantum integrated circuits”. Single and coupled qubit experiments, including qubits coupled to resonators, are reviewed along with a discussion of the strategy leading to these experiments. All currently known sources of qubit decoherence are summarized, including energy decay (T1), dephasing (T2), and measurement errors. A detailed description is given for our fabrication process and control electronics, which is directly scalable. With the demonstration of the basic operations needed for quantum computation, more complex algorithms are now within reach.