Direct measurement of quantum phase gradients in superfluid 4He flow.
We report a new kind of experiment in which we generate a known superfluid velocity in a straight tube and directly determine the phase difference across the tube's ends using a superfluid matter wave interferometer. By so doing, we quantitatively verify the relation between the superfluid velocity and the phase gradient of the condensate macroscopic wave function. Within the systematic error of the measurement (approximately 10%) we find nu(s)=Planck's/m4InvertedDeltaphi.
Sato
Yuki
Y
Physics Department, University of California, Berkeley, CA 94720, USA.
Joshi
Aditya
A
Packard
Richard
R