March 28, 1994 - March 28, 2027

  • Date:18ThursdayMay 2017

    AMO Special Seminar

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    Time
    11:15 - 12:00
    Title
    Quantum state monitoring and control via unsharp measurements
    Location
    Edna and K.B. Weissman Building of Physical Sciences
    Drory Auditorium
    Lecturer
    Dr. Hermann Uys
    Stellenbosch University, South Africa
    Organizer
    Department of Physics of Complex Systems
    Optics and Atomic Physics Seminar
    AbstractShow full text abstract about Typical experiments on quantum systems rely on open-loop dyn...»
    Typical experiments on quantum systems rely on open-loop dynamics that is probed with projective measurements. We explore the use of the broader class of POVM measurements allowed within quantum theory both for real-time monitoring of quantum states and quantum control. In particular, we discuss unsharp measurements as a tool to probe dynamic correlation functions during quantum quench dynamics in many particle spin systems. We derive an unsharp measurement protocol applicable to arbitrary spin, and find the surprising result that projective measurements allow exact extraction of correlation functions in the case of spin 1/2. Secondly, I present a protocol for quantum state monitoring using sequential unsharp measurement that allows real-time state estimation with high fidelity. By combining measurement with feedback based on an a priori (potentially incorrect) assumption regarding the pre-measurement state, we show that one can drive the quantum state into the assumed state. We call this control by a self-fulfilling prophecy.
    Lecture