RQC Seminar

161st RQC Seminar

  • Speaker

    Mr. Kumar Saurav
    ( University of Southern California, USA )

  • Date

    14:00-15:00 (2:00 p.m.-3:00 p.m.), October 15, 2024 (Tuesday)

  • Venue

    Onsite( Wako Main Research 3F 345-347 Seminar Room/ 研究本館3階 セミナー室(345-347) C01）

  • Title

    Quantum Property Preservation

  • Inquiries

    rqc_info[at]ml.riken.jp

Abstract
How long can a quantum property be maintained in the presence of a decohering environment using only smooth Hamiltonian control and no other resources? In this talk I will answer this question, while providing an intuitive geometric interpretation of the control landscape. I will discuss the existence of control Hamiltonians which preserve the target indefinitely, and also controls with singularities and breakdown times, beyond which property preservation fails. In the second part of the talk I will discuss the application of this general theory to the enhancement of the sensitivity of a measurement of a qubit's frequency. We have demonstrated this using a superconducting qubit, achieving a signal-to-noise enhancement per measurement shot by a factor of 1.65 relative to standard Ramsey interferometry.

References:
1. K. Saurav and D.A. Lidar, “Quantum Property Preservation”. arXiv:2408.11262.
2. M. O. Hecht, K. Saurav, E. Vlachos, D.A. Lidar, E.M. Levenson-Falk, “Beating the Ramsey limit on sensing with deterministic qubit control”. arXiv:2408.15926.



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