245 research outputs found
Multi-step Bose-Einstein Condensation of Trapped Ideal Bose Gases
The Phenomenon of multi-step Bose-Einstein condensation (BEC) of a finite
number of non-interacting bosons in anisotropic traps has been demonstrated by
studing the populations on eight subsets of states. The cusp in the specific
heat is found to be associated with the crossover between subsets of states
involving Bose functions of different classes, as specified by their
behaviour at . {PACS: 03.75.Fi, 05.30.-d, 64.60.-i}Comment: 12 Pages with 3 PS figure
Effects of Peer Mentoring on Types of Mentor Support, Program Satisfaction and Graduate Student Stress: A Dyadic Perspective
Examines the effects of a graduate student peer-mentoring program from the perspectives of both members of the mentoring dyad, the mentors and proteges. Results indicate that peer mentoring provides students with both increased levels of psychosocial and instrumental support, and that those with high levels of support are more satisfied with their peer mentoring relationships
Mentoring and Self-Management Career Strategies For Entrepreneurs
The purpose of this article is to examine the literature on self management and mentoring to develop practical methods of enhancing the career success of entrepreneurs. The authors believe that both behavioural and cognitive self-management strategies can be useful to entrepreneurs. These techniques include goal-setting, self-observation, self-rewards, cueing, self-talk, visualization and the active reframing of obstacles into opportunities. In addition, the varying roles and functions of mentors, including emotional, vocational and role modelling support, will have many positive benefits for both entrepreneurial proteges and mentors. Recommendations for furture research and an entrepreneurial model of career development are provided
Mentoring and Self-Management Career Strategies For Entrepreneurs
The purpose of this article is to examine the literature on self management and mentoring to develop practical methods of enhancing the career success of entrepreneurs. The authors believe that both behavioural and cognitive self-management strategies can be useful to entrepreneurs. These techniques include goal-setting, self-observation, self-rewards, cueing, self-talk, visualization and the active reframing of obstacles into opportunities. In addition, the varying roles and functions of mentors, including emotional, vocational and role modelling support, will have many positive benefits for both entrepreneurial proteges and mentors. Recommendations for furture research and an entrepreneurial model of career development are provided
Master-slave principle applied to an electrically tunable swept source-OCT system
In this communication, we evaluate the suitability of Master-Slave (MS) optical coherence tomography (OCT) for processing of interferograms generated by an interferometer driven by an akinetic, electrically-tunable swept source from Insight with an ultra-large instantaneous coherence length. The akinetic source is programmed to sweep linearly, but within the sweep, at predictable times, the laser tuning introduces invalid regions in the interferogram, which are normally removed post-acquisition using a pre-calibration file. This makes sure that any optical frequency component is used once only and enables correct operation of a Fourier transform (FT). A FT applied to an unprocessed emitted spectrum leads to wide and numerous peaks in the A-scan. MS processing was introduced to avoid the necessary corrections demanded by conventional FT signal processing or its derivatives. The MS procedure consists of comparing photo-detected signals at the output of two interferometers, a Slave and a Master interferometer. The MS method was advanced along two avenues, either by using (i) electricallygenerated master signals (making use of the same interferometer twice) or (ii) optically-generated master signal via a recently introduced MS down-conversion procedure. We apply both avenues to the Insight source. Approach (i) tests the MS principle as an alternative to the Insight file correction while (ii) demonstrates near coherencelimited operation at a large axial range (>80 mm) for which a too-high sampling rate digitizer would have been needed. In this communication, we evaluate for the first time the suitability of the MS procedure to OCT measurements performed with the akinetic swept source commercialized by Insight. Two modalities are evaluated to implement the MS processing, based on: (i) digital generation of the master signals using the OCT interferometer and (ii) down conversion using a second interferometer driven by the swept source
Dynamics of collapsing and exploding Bose-Einstein condensate
Recently, Donley et al. performed an experiment on the dynamics of collapsing
and exploding Bose-Einstein condensates by suddenly changing the scattering
length of atomic interaction to a large negative value on a preformed repulsive
condensate of Rb atoms in an axially symmetric trap. Consequently, the
condensate collapses and ejects atoms via explosions. We show that the accurate
numerical solution of the time-dependent Gross-Pitaevskii equation with axial
symmetry can explain some aspects of the dynamics of the collapsing condensate.Comment: 4 latex pages, 3 postscript figure
Bose-Einstein condensation thermodynamics of a trapped gas with attractive interaction
We study the Bose-Einstein condensation of an interacting gas with attractive
interaction confined in a harmonic trap using a semiclassical two-fluid
mean-field model. The condensed state is described by converged numerical
solution of the Gross-Pitaevskii equation. By solving the system of coupled
equations of this model iteratively we obtain converged results for the
temperature dependencies of the condensate fraction, chemical potential, and
internal energy for the Bose-Einstein condensate of Li atoms.Comment: Five latex pages, four postscript figures, Accepted in Physica
Stability and collapse of a coupled Bose-Einstein condensate
The dynamics of a coupled Bose-Einstein condensate involving trapped atoms in
two quantum states is studied using the time-dependent Gross-Pitaevskii
equation including an interaction which can transform atoms from one state to
the other. We find interesting oscillation of the number of atoms in each of
the states. For all repulsive interactions, stable condensates are formed. When
some of the atomic interactions are attractive, the possibility of collapse is
studied by including an absorptive contact interaction and a quartic three-body
recombination term. One or both components of the condensate may undergo
collapse when one or more of the nonlinear terms are attractive in nature.Comment: 14 Latex pages, 6 postscript figure
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