Individual topological tunnelling events of a quantum field probed through their macroscopic consequences

Mitrabhanu Sahu, Myung Ho Bae, Andrey Rogachev, David Pekker, Tzu Chieh Wei, Nayana Shah, Paul M. Goldbart, Alexey Bezryadin

Research output: Contribution to journalArticlepeer-review

Abstract

Phase slips are topological fluctuations that carry the superconducting order-parameter field between distinct current-carrying states. Owing to these phase slips, superconducting nanowires acquire electrical resistance. In such wires, it is well known that at higher temperatures phase slips occur through the process of thermal barrier-crossing by the order-parameter field. At low temperatures, the general expectation is that phase slips should proceed through quantum tunnelling events, which are known as quantum phase slips. However, resistive measurements have produced evidence both for and against the occurrence of quantum phase slips. Here, we report evidence for the observation of individual quantum phase-slip events in homogeneous ultranarrow wires at high bias currents. We accomplish this through measurements of the distribution of switching currents for which the width exhibits a rather counter-intuitive, monotonic increase with decreasing temperature. Importantly, measurements show that in nanowires with larger critical currents, quantum fluctuations dominate thermal fluctuations up to higher temperatures.

Original languageEnglish (US)
Pages (from-to)503-508
Number of pages6
JournalNature Physics
Volume5
Issue number7
DOIs
StatePublished - Jul 2009

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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