1,439 research outputs found
Persistent superfluid flow arising from the He-McKellar-Wilkens effect in molecular dipolar condensates
We show that the He-McKellar-Wilkens effect can induce a persistent flow in a
Bose-Einstein condensate of polar molecules confined in a toroidal trap, with
the dipolar interaction mediated via an electric dipole moment. For
Bose-Einstein condensates of atoms with a magnetic dipole moment, we show that
although it is theoretically possible to induce persistent flow via the
Aharonov-Casher effect, the strength of electric field required is prohibitive.
We also outline an experimental geometry tailored specifically for observing
the He-McKellar-Wilkens effect in toroidally-trapped condensates.Comment: 5 pages 2 figure
Infrared spectra of C2H4 dimer and trimer
Spectra of ethylene dimers and trimers are studied in the nu11 and (for the
dimer) nu9 fundamental band regions of C2H4 (~2990 and 3100 cm-1) using a
tunable optical parametric oscillator source to probe a pulsed supersonic slit
jet expansion. The deuterated trimer has been observed previously, but this
represents the first rotationally resolved spectrum of (C2H4)3. The results
support the previously determined cross-shaped (D2d) dimer and barrel-shaped
(C3h or C3) trimer structures. However, the dimer spectrum in the nu9
fundamental region of C2H4 is apparently very perturbed and a previous
rotational analysis is not well verified.Comment: 21 pages, 4 figure
Some Physical Properties of Aqueous Solutions of Cetyl Trimethyl Ammonium Bromide
This work is chiefly concerned with the viscous properties produced when certain phenolic compounds are added to an aqueous solution of cetyl trimethyl ammonium bromide (CTAB)
Suppressing Proton Decay By Separating Quarks And Leptons
Arkani-Hamed and Schmaltz (AS) have shown that proton stability need not
originate from symmetries in a high energy theory. Instead the proton decay
rate is suppressed if quarks and leptons are spatially separated in a compact
extra dimension. This separation may be achieved by coupling five dimensional
fermions to a bulk scalar field with a non-trivial vacuum profile and requires
relationships between the associated quark and lepton Yukawa couplings. We
hypothesise that these relationships are the manifestation of an underlying
symmetry. We further show that the AS proposal may suggest that proton
stability \emph{is} the result of an underlying symmetry, though not
necessarily the traditional baryon number symmetry.Comment: 4 pages, references added to match published versio
Electric dipole rovibrational transitions in HD molecule
The rovibrational electric dipole transitions in the ground electronic state
of the HD molecule are studied. A simple, yet rigorous formula is derived for
the transition rates in terms of the electric dipole moment function ,
which is calculated in a wide range of . Our numerical results for
transition rates are in moderate agreement with experiments and previous
calculations, but are at least an order of magnitude more accurate.Comment: 7 pages, 1 figur
Three new infrared bands of the He-OCS complex
Three new infrared bands of the weakly-bound He-OCS complex are studied,
using tunable lasers to probe a pulsed supersonic slit jet expansion. They
correspond to the (0400) <-- (0000), (1001)<-- (0000), and (0401) <-- (0000)
transitions of OCS at 2105, 2918, and 2937 cm-1, respectively. The latter band
is about 7900 times weaker than the previously studied OCS nu1 fundamental.
Vibrational shifts relative to the free OCS monomer are found to be additive.
Since carbonyl sulfide has previously been shown to be a valuable probe of
superfluid quantum solvation effects in helium clusters and droplets, the
present results could be useful for future studies of vibrational effects in
such systems.Comment: 16 pages, 1 figure, 4 table
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