title: Prediction and retrodiction for a continuously monitored superconducting qubit.
abstract: The quantum state of a superconducting transmon qubit inside a three-dimensional cavity is monitored by transmission of a microwave field through the cavity. The information inferred from the measurement record is incorporated in a density matrix ρ_{t}, which is conditioned on probe results until t, and in an auxiliary matrix E_{t}, which is conditioned on probe results obtained after t. Here, we obtain these matrices from experimental data and we illustrate their application to predict and retrodict the outcome of weak and strong qubit measurements.
authors: Department of Physics, Washington University, St. Louis, Missouri 63130, USA.
authors: D
authors: D
authors: Tan
authors: Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, California 94720, USA.
authors: S J
authors: SJ
authors: Weber
authors: Quantum Nanoelectronics Laboratory, Department of Physics, University of California, Berkeley, California 94720, USA.
authors: I
authors: I
authors: Siddiqi
authors: Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark.
authors: K
authors: K
authors: Mølmer
authors: Department of Physics, Washington University, St. Louis, Missouri 63130, USA.
authors: K W
authors: KW
authors: Murch