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

J. Kinnunen*, P. Törmä, J. P. Pekola

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

5 Citations (Scopus)
159 Downloads (Pure)

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.

Original languageEnglish
Article number020506
Pages (from-to)1-4
Number of pages4
JournalPhysical Review B
Volume68
Issue number2
DOIs
Publication statusPublished - 30 Jul 2003
MoE publication typeA1 Journal article-refereed

Keywords

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

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