  We show an efficient purification protocol in solid-state qubits by replacing
the usual bilateral CNOT gate by the bilateral iSWAP gate. We also show that
this replacement can be applied to breeding and hashing protocols, which are
useful for quantum state purification. These replacements reduce the number of
fragile and cumbersome two-qubit operations, making more feasible
quantum-information-processing with solid-state qubits. As examples, we also
present quantitative analyses for the required time to perform state
purification using either superconducting or semiconducting qubits.
