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arXiv · 1707.00656

Realization of a $\Lambda$ system with metastable states of a capacitively-shunted fluxonium

Nathan Earnest·Srivatsan Chakram·Yao Lu·Nicholas Irons·Ravi K. Naik·Nelson Leung·Leo Ocola·David A. Czaplewski·Brian Baker·Jay Lawrence·Jens Koch·David I. Schuster
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Abstract

We realize a $\Lambda$ system in a superconducting circuit, with metastable states exhibiting lifetimes up to 8\,ms. We exponentially suppress the tunneling matrix elements involved in spontaneous energy relaxation by creating a "heavy" fluxonium, realized by adding a capacitive shunt to the original circuit design. The device allows for both cavity-assisted and direct fluorescent readout, as well as state preparation schemes akin to optical pumping. Since direct transitions between the metastable states are strongly suppressed, we utilize Raman transitions for coherent manipulation of the states.

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Nathan Earnest, Srivatsan Chakram, Yao Lu, Nicholas Irons, Ravi K. Naik, Nelson Leung, Leo Ocola, David A. Czaplewski, Brian Baker, Jay Lawrence, Jens Koch, David I. Schuster. 2017-07-03. Realization of a $\Lambda$ system with metastable states of a capacitively-shunted fluxonium. https://doi.org/10.1103/physrevlett.120.150504

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