R. Zieve

Observation of quantized circulation in superfluid 3He-B

We report the first observation of quantized circulation in superfluid {sup 3}He-{ital B}. The apparatus consists of a straight vibrating wire immersed in liquid {sup 3}He, which is cooled by a rotating nuclear demagnetization cryostat. The experiment is carried out at about 250 {mu}K. The superfluid at this temperature is in the ballistic quasiparticle regime. Circulation around the wire is found to be stable only when it takes on the values {minus}{ital h}/2{ital m}{sub 3}, 0, and +{ital h}/2{ital m}{sub 3}, where {ital h} is Plancks constant and {ital m}{sub 3} is the mass of the {sup 3}He atom. This experiment confirms that superfluid {sup 3}He-{ital B} is a Cooper-paired superfluid with a macroscopic quantum wave function.

Observation of quantized circulation in superfluid sup 3 He- B

We report the first observation of quantized circulation in superfluid {sup 3}He-{ital B}. The apparatus consists of a straight vibrating wire immersed in liquid {sup 3}He, which is cooled by a rotating nuclear demagnetization cryostat. The experiment is carried out at about 250 {mu}K. The superfluid at this temperature is in the ballistic quasiparticle regime. Circulation around the wire is found to be stable only when it takes on the values {minus}{ital h}/2{ital m}{sub 3}, 0, and +{ital h}/2{ital m}{sub 3}, where {ital h} is Plancks constant and {ital m}{sub 3} is the mass of the {sup 3}He atom. This experiment confirms that superfluid {sup 3}He-{ital B} is a Cooper-paired superfluid with a macroscopic quantum wave function.

New experiments on quantization of circulation in superfluid4He

We measure circulation in superfluid4He around a thin vibrating wire which can serve as the core of a vortex. As well as confirming earlier measurements of the quantum of circulation, our data yield new information on the dynamics of transitions between stable circulation states. A situation in which a vortex line partially detaches from the wire, with the free end precessing about the wire, is observed.

Measurements of circulation in superfluid 3He-B using a vibrating wire

Abstract We have measured fluid circulation in superfluid 3 He-B. The apparatus consists of a straight vibrating wire which is mounted in a 3 He cell on a rotating millikelvin cryostat operating at temperatures in the ballistic quasiparticle regime. Circulation around the wire is found to be stable only when it takes on values -h/2m 3 , 0 , +h/2m 3 where h is Plancks constant and m 3 is the mass of the 3 He atom.

Continuously pumped rotating millikelvin cryostat

Abstract We report the construction of a rotating nuclear demagnetization cryostat which can be continuously operated. The refrigerator employs a quadruple concentric rotating vacuum seal. The minimum 3He temperature of this cryostat in the stationary state is 165 μK. In the rotating state there is a relatively large heat leak which depends both on the rotation rate and on the field in the main demagnetization magnet.

A mechanical measurement of textural relaxation in superfluid3He-A at very low temperatures

We have studied superfluid3He-A textures by a mechanical method in the very low temperature limit, T/Tc ≈ 0.14. The damping of a vibrating wire viscometer is affected by the structure of the 1-vector texture near the wire. The texture is disturbed by a violent motion of the wire. The relaxation of the texture, back to equilibrium, is then observed through changes in the damping of the wires motion.

Experiments on quantized circulation in superfluid 3He

This paper provides a brief description of recent experiments measuring the fluid circulation in 3He. In the B phase, the circulation around a 16 μm diameter wire is found to be quantized in units of h/2 m3. Possible future experiments are also described.