8,218 research outputs found
Remarks on the derivation of Gross-Pitaevskii equation with magnetic Laplacian
The effective dynamics for a Bose-Einstein condensate in the regime of high
dilution and subject to an external magnetic field is governed by a magnetic
Gross-Pitaevskii equation. We elucidate the steps needed to adapt to the
magnetic case the proof of the derivation of the Gross-Pitaevskii equation
within the "projection counting" scheme
Rotational excitation of methylidynium (CH+) by a helium atom at high temperature
We aim to obtain accurate rate coefficients for the collisional excitation of
CH+ by He for high gas temperatures. The ab initio coupled-cluster [CCSD(T)]
approximation was used to compute the interaction potential energy. Cross
sections are then derived in the close coupling (CC) approach and rate
coefficients inferred by averaging these cross sections over a
Maxwell-Boltzmann distribution of kinetic energies. Cross sections are
calculated up to 10'000 cm^-1 for J ranging from 0 to 10. Rate coefficients are
obtained at high temperatures up to 2000 K.Comment: 4 pages, 3 figures, table with rate coefficients, accepted for
publication by A&
A room temperature 19-channel magnetic field mapping device for cardiac signals
We present a multichannel cardiac magnetic field imaging system built in
Fribourg from optical double-resonance Cs vapor magnetometers. It consists of
25 individual sensors designed to record magnetic field maps of the beating
human heart by simultaneous measurements on a grid of 19 points over the chest.
The system is operated as an array of second order gradiometers using
sophisticated digitally controlled feedback loops.Comment: 3 pages, 3 figures, submitted to Applied Physics Letter
Experiences of the Pre and Post Retirement Period of Female Elite Artistic Gymnasts: An Exploratory Study
This study explored retirement experiences of eight, female, former elite artistic gymnasts. Particular attention was afforded to coping strategies employed and dynamics of gymnast’s relationships with significant members of their social support network, in light of identity impact, across the retirement transition period. Retrospective, semi-structured interviews were conducted, transcripts were analysed through content analysis, and represented via pen profiles. Pre-retirement planning emerged as fundamental to the quality of the retirement transition. Keeping in contact with sport was the most frequently cited coping strategy. Social support networks adjusted pre- to post-retirement, identifying parents and partners as the consistent members of these networks across the transition. Findings provide formative recommendations to enhance the post-career education within current lifestyle management programmes, and for the design of a transitional support programme for gymnasts. The study findings may be of relevance for policy and practice in elite sport transitions more generally
Experiences of the Pre and Post Retirement Period of Female Elite Artistic Gymnasts: An Exploratory Study
his study explored retirement experiences of eight, female, former elite artistic gymnasts. Particular attention was afforded to coping strategies employed and dynamics of gymnast’s relationships with significant members of their social support network, in light of identity impact, across the retirement transition period. Retrospective, semi-structured interviews were conducted, transcripts were analysed through content analysis, and represented via pen profiles. Pre-retirement planning emerged as fundamental to the quality of the retirement transition. Keeping in contact with sport was the most frequently cited coping strategy. Social support networks adjusted pre- to post-retirement, identifying parents and partners as the consistent members of these networks across the transition. Findings provide formative recommendations to enhance the post-career education within current lifestyle management programmes, and for the design of a transitional support programme for gymnasts. The study findings may be of relevance for policy and practice in elite sport transitions more generally
Effective non-linear dynamics of binary condensates and open problems
We report on a recent result concerning the effective dynamics for a mixture
of Bose-Einstein condensates, a class of systems much studied in physics and
receiving a large amount of attention in the recent literature in mathematical
physics; for such models, the effective dynamics is described by a coupled
system of non-linear Sch\"odinger equations. After reviewing and commenting our
proof in the mean field regime from a previous paper, we collect the main
details needed to obtain the rigorous derivation of the effective dynamics in
the Gross-Pitaevskii scaling limit.Comment: Corrected typos, updated reference
Resonant Formation of Molecules in Deuterium: An Atomic Beam Measurement of Muon Catalyzed dt Fusion
Resonant formation of molecules in collisions of muonic tritium
() on D was investigated using a beam of atoms,
demonstrating a new direct approach in muon catalyzed fusion studies. Strong
epithermal resonances in formation were directly revealed for the
first time. From the time-of-flight analysis of fusion
events, a formation rate consistent with times the theoretical prediction was obtained. For the largest
peak at a resonance energy of eV, this corresponds to a rate
of s, more than an order of magnitude larger
than those at low energies.Comment: To appear in Phys. Rev. Let
Sensitivity of double resonance alignment magnetometers
We present an experimental study of the intrinsic magnetometric sensitivity
of an optical/rf-frequency double resonance magnetometer in which linearly
polarized laser light is used in the optical pumping and detection processes.
We show that a semi-empirical model of the magnetometer can be used to describe
the magnetic resonance spectra. Then, we present an efficient method to predict
the optimum operating point of the magnetometer, i.e., the light power and rf
Rabi frequency providing maximum magnetometric sensitivity. Finally, we apply
the method to investigate the evolution of the optimum operating point with
temperature. The method is very efficient to determine relaxation rates and
thus allowed us to determine the three collisional disalignment cross sections
for the components of the alignment tensor. Both first and second harmonic
signals from the magnetometer are considered and compared
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