Centre for the Condensed-Matter Science and Technology, Harbin Institute of Technology, Harbin 150001, China;Department of Physics, College of Science, Yanbian University, Yanji 133002, China
Abstract:
We present a scheme for implementing a three-qubit phase
gate via manipulating rf superconducting quantum interference device
(SQUID) qubits in the decoherence-free subspace with respect to
cavity decay. Through appropriate changes of the coupling constants
between rf SQUIDs and cavity, the scheme can be realized only in one
step. A high fidelity is obtained even in the presence of
decoherence.