title: Oscillatory motion: quantum whistling in superfluid helium-4.
abstract: Fundamental considerations predict that macroscopic quantum systems such as superfluids and the electrons in superconductors will undergo oscillatory motion when forced through a small constriction. Here we induce these oscillations in superfluid helium-4 (4He) by pushing it through an array of nanometre-sized apertures. The oscillations, which are detected as an audible whistling sound, obey the so-called Josephson frequency relation and occur coherently among all the apertures. The discovery of this property in 4He at the relatively high temperature of 2 K (2,000 times higher than the temperature at which a related but different phenomenon occurs in 3He) may pave the way for a new class of practical rotation sensors of unprecedented precision.
authors.affiliation: Physics Department, University of California, Berkeley, California 94720, USA.
authors.forename: E
authors.initials: E
authors.lastname: Hoskinson
authors.forename: R E
authors.initials: RE
authors.lastname: Packard
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Haard