Service Communautaire d'Information sur la Recherche et le Développement - CORDIS

Back action of RF-SET readout of qubits

We have used a Single Electron Transistor operated in the Radio Frequency mode (RF-SET) to read out the quantum information of a single Cooper-pair Box, which acts as a qubit. We have analysed the frequency dependent back action from the RF-SET on the qubits and are able to calculate relaxation and decoherence times from our model. The back action is due both to shot noise and to quantum fluctuations of the SET. The conclusion is that relaxation can be minimized by increasing the qubit energy splitting. Another conclusion is that the dephasing can be drastically reduced by turning of the bias of the SET and by turning on the Coulomb blockade in the SET, by changing the gate voltage of the SET.

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Microtechnology and nanoscience
SE-41296 Gothenburg