Driven dynamics and rotary echo of a qubit tunably coupled to a harmonic oscillator.
We have investigated the driven dynamics of a superconducting flux qubit that is tunably coupled to a microwave resonator. We find that the qubit experiences an oscillating field mediated by off-resonant driving of the resonator, leading to strong modifications of the qubit Rabi frequency. This opens an additional noise channel, and we find that low-frequency noise in the coupling parameter causes a reduction of the coherence time during driven evolution. The noise can be mitigated with the rotary-echo pulse sequence, which, for driven systems, is analogous to the Hahn-echo sequence.
Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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Gustavsson
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Yan
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Forn-Díaz
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Bolkhovsky
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Braje
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Fitch
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Harrabi
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Lennon
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Miloshi
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Murphy
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Turek
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Weir
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Yoshihara
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Nakamura
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