Coherent control of macroscopic quantum states in a single-Cooper-pair box

Y. Nakamura (), Yu. A. Pashkin and J. S. Tsai
Additional contact information
Y. Nakamura: NEC Fundamental Research Laboratories
Yu. A. Pashkin: CREST, Japan Science and Technology Corporation (JST)
J. S. Tsai: NEC Fundamental Research Laboratories

Nature, 1999, vol. 398, issue 6730, 786-788

Abstract: Abstract A nanometre-scale superconducting electrode connected to a reservoir via a Josephson junction constitutes an artificial two-level electronic system: a single-Cooper-pair box. The two levels consist of charge states (differing by 2e, where e is the electronic charge) that are coupled by tunnelling of Cooper pairs through the junction. Although the two-level system is macroscopic, containing a large number of electrons, the two charge states can be coherently superposed1,2,3,4. The Cooper-pair box has therefore been suggested5,6,7 as a candidate for a quantum bit or ‘qubit’—the basic component of a quantum computer. Here we report the observation of quantum oscillations in a single-Cooper-pair box. By applying a short voltage pulse via a gate electrode, we can control the coherent quantum state evolution: the pulse modifies the energies of the two charge states non-adiabatically, bringing them into resonance. The resulting state—a superposition of the two charge states—is detected by a tunnelling current through a probe junction. Our results demonstrate electrical coherent control of a qubit in a solid-state electronic device.

Date: 1999
References: Add references at CitEc
Citations: View citations in EconPapers (12)

Downloads: (external link)
https://www.nature.com/articles/19718 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:398:y:1999:i:6730:d:10.1038_19718

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/19718

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().