7,297 research outputs found
Superfluidity in Three-species Mixture of Fermi Gases across Feshbach Resonances
In this letter a generalization of the BEC-BCS crossover theory to a
multicomponent superfluid is presented by studying a three-species mixture of
Fermi gas across two Feshbach resonances. At the BEC side of resonances, two
kinds of molecules are stable which gives rise to a two-component Bose
condensate. This two-component superfluid state can be experimentally
identified from the radio-frequency spectroscopy, density profile and short
noise measurements. As approaching the BCS side of resonances, the
superfluidity will break down at some point and yield a first-order quantum
phase transition to normal state, due to the mismatch of three Fermi surfaces.
Phase separation instability will occur around the critical regime.Comment: 4 pages, 3 figures, revised versio
On the error term in Weyl's law for the Heisenberg manifolds (II)
In this paper we study the mean square of the error term in the Weyl's law of
an irrational -dimensional Heisenberg manifold . An asymptotic formula
is established
Effective Vortex Pinning in MgB2 thin films
We discuss pinning properties of MgB2 thin films grown by pulsed-laser
deposition (PLD) and by electron-beam (EB) evaporation. Two mechanisms are
identified that contribute most effectively to the pinning of vortices in
randomly oriented films. The EB process produces low defected crystallites with
small grain size providing enhanced pinning at grain boundaries without
degradation of Tc. The PLD process produces films with structural disorder on a
scale less that the coherence length that further improves pinning, but also
depresses Tc
Granular Media under Vibration in Zero Gravity: Transition from Rattling to Granular Gas
We report on different experimental behaviours of granular dissipative matter
excited by vibration as studied during the 43rd ESA campaign of Airbus A300-0g
from CNES. The effect of g-jitter is quantified through the generation of a
rattle effect. The French-European team's electromagnetic set-up is used, with
20Hz cam recording and high speed camera for a short duration (1s) during each
parabola.Comment: Poudres et Grains 201
Two-photon interference with two independent pseudo-thermal sources
The nature of two-photon interference is a subject that has aroused renewed
interest in recent years and is still under debate. In this paper we report the
first observation of two-photon interference with independent pseudo-thermal
sources in which sub-wavelength interference is observed. The phenomenon may be
described in terms of the classical statistical distribution of the two sources
and their optical transfer functions.Comment: Phys. Rev. A 74, 053807 (2006
Performance data of US Naval Observatory VLG-11 hydrogen masers since September, 1983
In 1983, two VLC-11 masers were delivered to the U.S. Naval Observatory by the Smithsonian Astrophysical Observatory. Last year the short-term stability of these masers was reported and the effect of this short-term stability on timekeeping performance was examined. Since the date of installation, 13 September 1983, data on the masers' long-term performance have been accumulated. The Allan variance, agma(tau), of the relative frequency between the masers reaches a minimum of about 4 parts in 10 to the 16th power at averaging times 5,000 seconds and rises at longer averaging times due, at least partly, to systematic frequency drift. The systematic frequency drifts, expressed in units of fractional frequency difference per day are discussed
Looking at Vector Space and Language Models for IR using Density Matrices
In this work, we conduct a joint analysis of both Vector Space and Language
Models for IR using the mathematical framework of Quantum Theory. We shed light
on how both models allocate the space of density matrices. A density matrix is
shown to be a general representational tool capable of leveraging capabilities
of both VSM and LM representations thus paving the way for a new generation of
retrieval models. We analyze the possible implications suggested by our
findings.Comment: In Proceedings of Quantum Interaction 201
The Transporter Classification Database: recent advances
The Transporter Classification Database (TCDB), freely accessible at http://www.tcdb.org, is a relational database containing sequence, structural, functional and evolutionary information about transport systems from a variety of living organisms, based on the International Union of Biochemistry and Molecular Biology-approved transporter classification (TC) system. It is a curated repository for factual information compiled largely from published references. It uses a functional/phylogenetic system of classification, and currently encompasses about 5000 representative transporters and putative transporters in more than 500 families. We here describe novel software designed to support and extend the usefulness of TCDB. Our recent efforts render it more user friendly, incorporate machine learning to input novel data in a semiautomatic fashion, and allow analyses that are more accurate and less time consuming. The availability of these tools has resulted in recognition of distant phylogenetic relationships and tremendous expansion of the information available to TCDB users
Magnetically asymmetric interfaces in a (LaMnO)/(SrMnO) superlattice due to structural asymmetries
Polarized neutron reflectivity measurements of a ferromagnetic
[(LaMnO)/(SrMnO)] superlattice reveal a modulated
magnetic structure with an enhanced magnetization at the interfaces where
LaMnO was deposited on SrMnO (LMO/SMO). However, the opposite
interfaces (SMO/LMO) are found to have a reduced ferromagnetic moment. The
magnetic asymmetry arises from the difference in lateral structural roughness
of the two interfaces observed via electron microscopy, with strong
ferromagnetism present at the interfaces that are atomically smooth over tens
of nanometers. This result demonstrates that atomic-scale roughness can
destabilize interfacial phases in complex oxide heterostructures.Comment: 5 pages, 4 figure
Light Element Abundance Patterns in the Orion Association: I) HST Observations of Boron in G-dwarfs
The boron abundances for two young solar-type members of the Orion
association, BD -6 1250 and HD 294297, are derived from HST STIS spectra of the
B I transition at 2496.771 A. The best-fit boron abundances for the target
stars are 0.13 and 0.44 dex lower than the solar meteoritic value of log
e(B)=2.78. An anticorrelation of boron and oxygen is found for Orion when these
results are added to previous abundances obtained for 4 B-type stars and the
G-type star BD -5 1317. An analysis of the uncertainties in the abundance
calculations indicates that the observed anticorrelation is probably real. The
B versus O relation observed in the Orion association does not follow the
positive correlation of boron versus oxygen which is observed for the field
stars with roughly solar metallicity. The observed anticorrelation can be
accounted for by a simple model in which two poorly mixed components of gas
(supernova ejecta and boron-enriched ambient medium) contribute to the new
stars that form within the lifetime of the association. This model predicts an
anticorrelation for Be as well, at least as strong as for boron.Comment: 16 pages + 1 table + 7 figures, accepted for publication in Ap
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