Coherent quantum phase slip

O. V. Astafiev, L. B. Ioffe, S. Kafanov, Yu A. Pashkin, K. Yu Arutyunov, D. Shahar, O. Cohen, J. S. Tsai

Research output: Contribution to journalArticlepeer-review

167 Scopus citations

Abstract

A hundred years after the discovery of superconductivity, one fundamental prediction of the theory, coherent quantum phase slip (CQPS), has not been observed. CQPS is a phenomenon exactly dual to the Josephson effect; whereas the latter is a coherent transfer of charges between superconducting leads, the former is a coherent transfer of vortices or fluxes across a superconducting wire. In contrast to previously reported observations of incoherent phase slip, CQPS has been only a subject of theoretical study. Its experimental demonstration is made difficult by quasiparticle dissipation due to gapless excitations in nanowires or in vortex cores. This difficulty might be overcome by using certain strongly disordered superconductors near the superconductor-insulator transition. Here we report direct observation of CQPS in a narrow segment of a superconducting loop made of strongly disordered indium oxide; the effect is made manifest through the superposition of quantum states with different numbers of flux quanta. As with the Josephson effect, our observation should lead to new applications in superconducting electronics and quantum metrology.

Original languageEnglish (US)
Pages (from-to)355-358
Number of pages4
JournalNature
Volume484
Issue number7394
DOIs
StatePublished - Apr 19 2012

All Science Journal Classification (ASJC) codes

  • General

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