Evolution and decay of a superconducting Josephson junction qubit due to partial measurement

Superconducting Josephson phase qubits have been shown to be a promising candidate for scalable quantum computing. In many such quantum computing algorithms, partial measurement of the quantum state is used to project the system into a required subspace. We experimentally study the effect of a partial measurement on our Josephson phase qubit using state tomography and high fidelity measurement capabilities. We also explore related multi-photon effects which appear naturally in such a system during state preparation, evolution and measurement.