The Observation and Measurement of Quantized Circulation in Superfluid HELIUM-3

Of the three known superfluids, (^4 He, superconducting electrons, and ^3 He), the first two are known to be described by a macroscopic wavefunction. As a direct consequence, these systems display quantisation of circulation. It has long been assumed that superfluid ^3He -B is also described by a macroscopic wavefunction and should also exhibit quantisation of circulation. This thesis describes the first measurements showing that circulation is quantised in superfluid ^3 He-B and showing that the quantum of circulation is h/2m_3 where h is Plancks constant and m_3 is the mass of a ^3He atom. This experiment confirms that superfluid ^3He is a Cooper paired superfluid described by a macroscopic wavefunction. ^{1,2,3} ftn^1J. Close, R. Zieve, J. C. Davis and R. E. Packard, Physica (Amsterdam) 165 & 166B, 57 (1990). ^2J. C. Davis, J. Close, R. Zieve and R. E. Packard, Phys. Rev. Lett. 66, 329 (1991). ^3J. C. Davis, R. Zieve, J. Close and R. E. Packard, Physica (Amsterdam) 169, 523 (1991).