  We propose a theoretical protocol for quantum logic gates between two
Josephson junction charge-phase qubits through the control of their coupling to
a large junction. In the low excitation limit of the large junction when
$E_{J}\gg E_{c}$, it behaves effectively as a quantum data-bus mode of a
harmonic oscillator. Our protocol is efficient and fast. In addition, it does
not require the data-bus to stay adiabatically in its ground state, as such it
can be implemented over a wide parameter regime independent of the data-bus
quantum state.
