Single-shot measurement of the Josephson charge qubit

O. Astafiev, Yu A. Pashkin, T. Yamamoto, Y. Nakamura, J. S. Tsai

Research output: Contribution to journalArticlepeer-review

80 Citations (Scopus)


We demonstrate single-shot readout of quantum states of the Josephson charge qubit. The quantum bits are transformed into and stored as classical bits (charge quanta) in a dynamic memory cell-a superconducting island. The transformation of state |1〉 (differing form state |0〉 by an extra Cooper pair) is a result of a controllable quasiparticle tunneling to the island. The charge is then detected by a conventional single-electron transistor, electrostatically decoupled from the qubit. We study relaxation dynamics in the system and obtain the readout efficiency of 87% and 93% for |1〉 and |0〉 states, respectively.

Original languageEnglish
Article number180507
Pages (from-to)180507-1-180507-4
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number18
Publication statusPublished - May 2004
Externally publishedYes


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