Time-Domain Investigation of Coupled Superconducting Qubits

We report on measurements of two coupled rf SQUID phase qubits. With both qubits initially in their ground states, the first is excited with a pi pulse. Being initially detuned they are brought into resonance with a coupling pulse that allows the qubits to be put into a maximally entangled state. By varying the length of the interaction time we are able to perform a full logical SWAP gate operation. The coherence times and Rabi amplitudes measured on these qubits are small when compared to quantum error correction limits.