Relaxation mechanisms of the fluxonium qubit

ORAL

Abstract

Fluxonium is a highly anharmonic artificial atom, which utilizes an inductance formed by an array of large Josephson junctions to shunt the junction of a Cooper-pair box. The first excited state transition frequency is widely tunable with flux, yet can be read out over the entire five octave range due to interactions of the 2nd excited state with the readout cavity, enabling a dispersive readout. We present T1 times of several fluxonium samples over the full range of flux dependent transition energies. By mapping out the qubit lifetimes we are able to distinguish between the contributions due to the Purcell effect and quantify dissipation internal to the qubit. With this understanding, we can design a qubit with minimized contribution from internal losses, which should push lifetimes further into the tens of microseconds. [1] V. E. Manucharyan et al., Science 326, 113 (2009).

*Work supported by IARPA, ARO and NSF.

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Authors

  • Nicholas Masluk

    • Yale University

  • Archana Kamal

    • Yale University
    • Applied Physics Department, Yale University

  • Vladimir Manucharyan

    • Yale University, Harvard University
    • Harvard University

  • Jens Koch

    • Northwestern University

  • Leonid Glazman

    • Yale University
    • Department of Physics, Yale University, 217 Prospect Street, New Haven, CT 06520, USA

  • Michel Devoret

    • Yale University
    • Departments of Physics and Applied Physics, Yale University, New Haven, CT 06520, USA
    • Applied Physics Department, Yale University