Measuring charge-based quantum bits by a superconducting single-electron transistor

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Journal Title

Journal ISSN

Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2003-07-30

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Mcode

Degree programme

Language

en

Pages

4
1-4

Series

PHYSICAL REVIEW B, Volume 68, issue 2

Abstract

Single-electron transistors have been proposed to be used as a read-out device for Cooper pair charge qubits. Here we show that a coupled superconducting transistor at a threshold voltage is much more effective in measuring the state of a qubit than a normal-metal transistor at the same voltage range. The effect of the superconducting gap is to almost completely block the current through the transistor when the qubit is in the logical state 1, compared to the mere diminishment of the current in the normal-metal case. The time evolution of the system is solved when the measuring device is driven out of equilibrium, the effect of higher-order contributions is examined and the setting is analyzed numerically for parameters accessible by lithographic aluminum structures.

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Keywords

charge-based quantum bits, single-electron transistor, superconductor

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Citation

Kinnunen , J , Törmä , P & Pekola , J P 2003 , ' Measuring charge-based quantum bits by a superconducting single-electron transistor ' , Physical Review B , vol. 68 , no. 2 , 020506 , pp. 1-4 . https://doi.org/10.1103/PhysRevB.68.020506