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| Coherent control of macroscopic quantum states in a single-Cooper-pair box |
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| Author(s): Nakamura Y, Pashkin YA, Tsai JS |
| Source: NATURE Volume: 398 Issue: 6730 Pages: 786-788 Published: APR 29 1999 |
| Times Cited: 1,152 References: 18 |
| 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 superposed(1-4). The Cooper-pair box has therefore been suggested(5-7) 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 nonadiabatically, 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. |
| Document Type: Article |
| Language: English |
| Reprint Address: Nakamura, Y (reprint author), NEC Fundamental Res Labs, Ibaraki, Osaka 3058051 Japan |
Addresses:
1. NEC Fundamental Res Labs, Ibaraki, Osaka 3058051 Japan
2. Japan Sci & Technol Corp, CREST, Kawaguchi, Saitama 3320012 Japan |
| Publisher: MACMILLAN MAGAZINES LTD, PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND |
| Subject Category: Multidisciplinary Sciences |
| IDS Number: 192BL |
| ISSN: 0028-0836 |
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