Quantum Coherence in a Superfluid Josephson Junction

Abstract

We report a new kind of experiment in which we take an array of nanoscale apertures that form a superfluid (4)He Josephson junction and apply quantum phase gradients directly along the array. We observe collective coherent behaviors from aperture elements, leading to quantum interference. Connections to superconducting and Bose-Einstein condensate Josephson junctions as well as phase coherence among the superfluid aperture array are discussed.

Superfluid helium interferometers

“…A large-area 4 He gyroscope with a long, multiturn path was demonstrated in 2011 by the Harvard group. 15 The total enclosed area is 225 cm 2 , 40 times larger than the sensing area of the first 3 He SHeQUID. If combined with recently demonstrated nonlinear amplification techniques, 2 superfluid interferometers have the potential to achieve the rotational sensitivity of the bestreported atom interferometers.…”

Dissipative dynamics of the Josephson effect in binary Bose-Einstein-condensed mixtures

“…In spite of wide application of the effect in devices for extremely highsensitivity measurements of currents, voltages, and magnetic fields the Josephson effect is still of interest in the fundamental modern physics. Like superconductors and Fermi superfluids, the Josephson effect is also inherent in Bose superfluids [12][13][14]. The effect has been observed by the mass flow of superfluid 4 He through nanoscale apertures coupling two bulk superfluid reservoirs.…”

Comparative analysis of optical-physical schemes of gyroscopes based on macroscopic quantum effects of superfluid helium isotopes (3He &4He)

“…It is unknown at this time if the SHeQUID can be scaled to these (and even larger) dimensions. A superfluid interferometer with 53 cm path length and 225 cm 2 sensing area in counter-wound reciprocal geometry has been recently developed [15].…”