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Seminars

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  • Title:Quantum computing and quantum optics with superconducting circuits
  • Start Date/Time:2018-10-16 / 13:20
  • End Date/Time :2018-10-16 / 15:10
    • Speaker:Prof. Io-Chun Hoi (Department of Physics,NTHU)
    • Place:Lecture Room A of NCTS, 4F, 3rd General Building, Nat'l Tsing Hua Univ.
    • Host:Prof. Germar Hoffmann (NTHU)
    • Abstract:

      In this talk, I will address quantum computing and quantum optics with superconducting circuits. In the first part of the talk, I will introduce the basics concepts of quantum computing, recent developments, decoherence and how to construct simple quantum algorithm with superconducting circuits. In the second part of the talk, I will address quantum optics with superconducting artificial atom. In particular, we embed a transmon at a distance from the end (mirror) of a transmission line [1]. By tuning the wavelength of the atom, we effectively change the normalized distance between atom and mirror, allowing us to effectively move the atom from a node to an antinode of the vacuum fluctuations. We probe the strength of vacuum fluctuations by measuring spontaneous emission rate of the atom. In the next experiments, we strongly couple a transmon to the field in a semi-infinite waveguide. When driving the qubit strongly on resonance such that a Mollow triplet appears, we observe a few percent amplitude gain for a weak probe at frequencies in between the triplet [2]. This amplification is not due to population inversion, but instead results from a four-photon process that converts energy from the strong drive to the weak probe.

      [1]  I.-C. Hoi et al. Nature Physics 11, 1045 (2015)

      [2]  P. Y. Wen et al. Physical Review Letters 120, 063603 (2018)

    • Detailed contents:
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