2,326 research outputs found
Superfluid phases of fermions with hybridized and orbitals
We explore the superfluid phases of a two-component Fermi mixture with
hybridized orbitals in optical lattices. We show that there exists a general
mapping of this system to the Lieb lattice. By using simple multiband models
with hopping between and -orbital states, we show that superfluid order
parameters can have a -phase difference between lattice sites, which is
distinct from the case with hopping between -orbitals. If the population
imbalance between the two spin species is tuned, the superfluid phase may
evolve through various phases due to the interplay between hopping,
interactions and imbalance. We show that the rich behavior is observable in
experimentally realizable systems.Comment: 13 pages, 11 figures. Published versio
Self-localization of magnon Bose-Einstein condensates in the ground state and on excited levels: from harmonic to box-like trapping potential
Long-lived coherent spin precession of 3He-B at low temperatures around 0.2
Tc is a manifestation of Bose-Einstein condensation of spin-wave excitations or
magnons in a magnetic trap which is formed by the order-parameter texture and
can be manipulated experimentally. When the number of magnons increases, the
orbital texture reorients under the influence of the spin-orbit interaction and
the profile of the trap gradually changes from harmonic to a square well, with
walls almost impenetrable to magnons. This is the first experimental example of
Bose condensation in a box. By selective rf pumping the trap can be populated
with a ground-state condensate or one at any of the excited energy levels. In
the latter case the ground state is simultaneously populated by relaxation from
the exited level, forming a system of two coexisting condensates.Comment: 4 pages, 5 figure
Effect of Mn and Mg dopants on vacancy defect formation in ammonothermal GaN
We have applied positron annihilation spectroscopy to study the formation of Ga vacancy related defects in Mg and Mn doped bulk GaN crystals grown by the ammonothermal method. We show that Mn doping has little or no effect on the formation of Ga vacancies, while Mg doping strongly suppresses their formation, in spite of both dopants leading to highly resistive material. We suggest the differences are primarily due to the hydrogen-dopant interactions. Further investigations are called for to draw a detailed picture of the atomic scale phe-nomena in the synthesis of ammonothermal GaN.Peer reviewe
Nanoelectronic thermometers optimised for sub-10 millikelvin operation
We report the cooling of electrons in nanoelectronic Coulomb blockade
thermometers below 4 mK. Above 7 mK the devices are in good thermal contact
with the environment, well isolated from electrical noise, and not susceptible
to self-heating. This is attributed to an optimised design that incorporates
cooling fins with a high electron-phonon coupling and on-chip electronic
filters, combined with a low-noise electronic measurement setup. Below 7 mK the
electron temperature is seen to diverge from the ambient temperature. By
immersing a Coulomb Blockade Thermometer in the 3He/4He refrigerant of a
dilution refrigerator, we measure a lowest electron temperature of 3.7 mK.Comment: 11 pages, 4 figures. (Fixed fitted saturation T_e on p9
Superfluid vortex front at T -> 0: Decoupling from the reference frame
Steady-state turbulent motion is created in superfluid 3He-B at low
temperatures in the form of a turbulent vortex front, which moves axially along
a rotating cylindrical container of 3He-B and replaces vortex-free flow with
vortex lines at constant density. We present the first measurements on the
thermal signal from dissipation as a function of time, recorded at 0.2 Tc
during the front motion, which is monitored using NMR techniques. Both the
measurements and the numerical calculations of the vortex dynamics show that at
low temperatures the density of the propagating vortices falls well below the
equilibrium value, i.e. the superfluid rotates at a smaller angular velocity
than the container. This is the first evidence for the decoupling of the
superfluid from the container reference frame in the zero-temperature limit.Comment: 4 pages, 4 figure
Achieving equity through 'gender autonomy': the challenges for VET policy and practice
This paper is based on research carried out in an EU Fifth Framework project on 'Gender and Qualification'. The research partners from five European countries investigated the impact of gender segregation in European labour markets on vocational education and training, with particular regard to competences and qualifications. The research explored the part played by gender in the vocational education and training experiences of (i) young adults entering specific occupations in child care, electrical engineering and food preparation/service (ii) adults changing occupations
Electromechanical film sensor device for dynamic force recordings from canine limbs
An equipment based on the electromechanical film (EMF) sensors was designed for the measurementof forces acting upon canine limbs. EMF forms an elastic electret, which generates on its surface an electric charge proportional to the the force applied on it. The EMF sensors were calibrated using a conventional material testing device with cyclic loads. The beagles were trained on a treadmill working at horizontal position or with either 15° uphill or downhill inclination. The treadmill belt speed varied from 2.5 km/h to 7.5 km/h. The force under the canine paws varied depending on the inclination of the treadmill. When the dogs ran uphill, weight-bearing on hind1imbs increased 11% but the weight-bearing 0n forelimbs did not change. Downhill running increased weight-bearing on forelimbs by 8% and decreased weight-bcaring of the hindlimbs by 5%. Immobilization of the right hind] imb increased weightbearing on both forelimbs by 7-25% and on the left hindlimb by 56%. One month after a 30° valgus osteotomy operation at the right tibia, the dynamic force recorded From the operated hindlimb was 69% of the control value. Three months after osteotomy, the weight-bearing of the operated limb approachednormal situation. Our results suggest that the EMF sensor is a reliable method for the measurement of dynamic forces acting on the weight-bearing limbs of the dogs
Differences and overlap in self-reported symptoms of bipolar disorder and borderline personality disorder
Background: Differential diagnosis between bipolar disorder (BD) and borderline personality disorder (BPD) is often challenging due to some overlap in symptoms and comorbidity of disorders. We investigated correlations in self-reported symptoms of BD and BPD in screening questionnaires at the levels of both total scores and individual items and explored overlapping dimensions. Methods: The McLean Screening Instrument (MSI) for BPD and the Mood Disorder Questionnaire (MDQ) for BD were filled in by patients with unipolar and bipolar mood disorders (n = 313) from specialized psychiatric care within a pilot study of the Helsinki University Psychiatric Consortium. Pearson's correlation coefficients between total scores and individual items of the MSI and the MDQ were estimated. Relationships between MDQ and MSI were evaluated by exploratory factor analysis (EFA). Results: The correlation between total scores of the MDQ and MSI was moderate (r = 0.431, P <0.001). Significant correlations were found between the MSI items of "impulsivity'' and "mood instability'' and all MDQ items (P <0.01). In the EFA, the MSI "impulsivity'' and "mood instability'' items had significant cross-loadings (0.348 and 0.298, respectively) with the MDQ factor. The MDQ items of "irritability'', "flight of thoughts'' and "distractibility'' (0.280, 0.210 and 0.386, respectively) cross-loaded on the MSI factor. Conclusions: The MDQ and MSI items of "affective instability'', "impulsivity'', "irritability'', "flight of thoughts'' and "distractibility'' appear to overlap in content. The other scale items are more disorder-specific, and thus, may help to distinguish BD and BPD. (C) 2015 Elsevier Masson SAS. All rights reserved.Peer reviewe
Novel Data Acquisition System for Silicon Tracking Detectors
We have developed a novel data acquisition system for measuring tracking
parameters of a silicon detector in a particle beam. The system is based on a
commercial Analog-to-Digital VME module and a PC Linux based Data Acquisition
System. This DAQ is realized with C++ code using object-oriented techniques.
Track parameters for the beam particles were reconstructed using off-line
analysis code and automatic detector position alignment algorithm.
The new DAQ was used to test novel Czochralski type silicon detectors. The
important silicon detector parameters, including signal size distributions and
signal to noise distributions, were successfully extracted from the detector
under study. The efficiency of the detector was measured to be 95 %, the
resolution about 10 micrometers, and the signal to noise ratio about 10.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 6 pages, LaTeX, 5 eps figures. PSN
TUGP00
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