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Interferometric Measurement of the Current-Phase Relationship of a Superfluid Weak Link



Stephen Eckel, Fred Jendrzejewski, Avinash Kumar, Christopher J. Lobb, Gretchen K. Campbell


Weak connections between superconductors or superfluids differ from classical links due to quantum coherence, which allows flow without resistance. Transport properties through such weak links can be described with a single function, the current-phase relationship, which serves as the quantum analog of the current-voltage relationship. Here, we present the first direct measurement of a current-phase relationship of a superfluid weak link. We interferometrically measure the phase gradient around a ring-shaped superfluid Bose-Einstein condensate containing a rotating weak link, allowing us to identify the current flowing around the ring. This technique can be extended to weak links in any phase-coherent quantum gas and can also measure current-phase relationships of excitations, such as solitonic-vortices. Such measurements may open new avenues of research in quantum transport.
Physical Review X


atomtronics, Bose-Einstein condensation, current-phase relationships, interference, Jospehson junctions, superfluidity, ultracold atoms, weak links


Eckel, S. , Jendrzejewski, F. , Kumar, A. , Lobb, C. and , G. (2014), Interferometric Measurement of the Current-Phase Relationship of a Superfluid Weak Link, Physical Review X, [online],, (Accessed June 25, 2024)


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Created September 22, 2014, Updated May 3, 2021