posted on 2023-06-07, 14:25authored byClaudia Eberlein, M.P.A. Jones, C.J. Vale, D. Sahagun, B.V. Hall, B.E. Sauer, K . Furusawa, D. Richardson, E.A. Hinds
A microscopic Ioffe–Pritchard trap is formed using a straight, current-carrying wire, together with suitable auxiliary magnetic fields. By measuring the distribution of cold rubidium atoms held in this trap, we detect a weak magnetic field component ?Bz parallel to the wire. This is produced by the current in the wire and is approximately periodic along the wire with period ? = 230 µm. We have measured this field at distances in the range y = 250–350 µm from the centre of the wire. Over this range we find that the decrease of the field is well described by the Bessel function K1(2py/?), as one would expect for the far field of a transversely oscillating current within the wire.
A BEC is used to measure the magnetic field close to a wire, which may be due to a helical current. This work provided the strongest indication yet as to what causes condensates to break up close to current-carrying structures. I did the calculations for the experimental team.