Microwave irradiation and quasiparticles in a superconducting double dot
Abstract
We study the interaction of the charge states of a superconducting double dot, comprising two superconducting islands coupled by a Josephson junction, with microwaves between 2 and 55 GHz. We observe resonant transitions between even-parity charge states at relatively low frequencies and breaking of Cooper pairs under higher-frequency irradiation, allowing our device to act as a click detector for microwave photons. By applying a magnetic field and tuning the pair-breaking energy, we perform spectroscopy on the environment in our cryostat and determine the temperature of a nonequilibrium photon bath. Finally, we exploit the band structure of our device to break Cooper pairs dependent on the symmetry of the initial Cooper pair state.
Citation
Lambert , N J , Esmail , A A , Pollock , F A , Edwards , M , Lovett , B W & Ferguson , A J 2017 , ' Microwave irradiation and quasiparticles in a superconducting double dot ' , Physical Review. B, Condensed matter and materials physics , vol. 95 , no. 23 , 235413 . https://doi.org/10.1103/PhysRevB.95.235413
Publication
Physical Review. B, Condensed matter and materials physics
Status
Peer reviewed
ISSN
1098-0121Type
Journal article
Description
Funding: UK EPSRC EP/K025562.Collections
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