Thermally Induced Losses in Ultra-Cold Atoms Magnetically Trapped Near Room-Temperature Surfaces

We have measured magnetic trap lifetimes of ultra-cold Rb87 atoms at distances of 5-1000 microns from surfaces of conducting metals with varying resistivity. Good agreement is found with a theoretical model for losses arising from near-field magnetic thermal noise, confirming the complications associated with holding trapped atoms close to conducting surfaces. A dielectric surface (silicon) was found in contrast to be so benign that we are able to evaporatively cool atoms to a Bose-Einstein condensate by using the surface to selectively adsorb higher energy atoms.Comment: Improved theory curve eliminates discrepancy. JLTP in pres

The Mystery of the Ramsey Fringe that Didn't Chirp

We use precision microwave spectroscopy of magnetically trapped, ultra-cold 87Rb to characterize intra- and inter-state density correlations. The cold collision shifts for both normal and condensed clouds are measured. The results verify the presence of the sometimes controversial "factors of two", in normal-cloud mean-field energies, both within a particular state and between two distinct spin species. One might expect that as two spin species decohere, the inter-state factor of two would revert to unity, but the associated frequency chirp one naively expects from such a trend is not observed in our data.Comment: Proceedings of the 18th International Conference on Atomic Physics (ICAP 2002

Decoherence-driven Cooling of a Degenerate Spinor Bose Gas

We investigate the relationship between the coherence of a partially Bose-condensed spinor gas and its temperature. We observe cooling of the normal component driven by decoherence as well the effect of temperature on decoherence rates.Comment: 4 pages, 2 figure

Theory of the Ramsey spectroscopy and anomalous segregation in ultra-cold rubidium

The recent anomalous segregation experiment of Lewandowski et al. (PRL, 88, 070403, 2002) shows dramatic, rapid internal state segregation for two hyperfine levels of rubidium. We simulate an effective one dimensional model of the system for experimental parameters and find reasonable agreement with the data. The Ramsey frequency is found to be insensitive to the decoherence of the superposition, and is only equivalent to the interaction energy shift for a pure superposition. A Quantum Boltzmann equation describing collisions is derived using Quantum Kinetic Theory, taking into account the different scattering lengths of the internal states. As spin-wave experiments are likely to be attempted at lower temperatures we examine the effect of degeneracy on decoherence by considering the recent experiment of Lewandowski et al. where degeneracy is around 10%. We also find that the segregation effect is only possible when transport terms are included in the equations of motion, and that the interactions only directly alter the momentum distributions of the states. The segregation or spin wave effect is thus entirely due to coherent atomic motion as foreseen in the experimental reportComment: 26 pages, 4 figures, to be published in J. Phys.

Schooling for violence and peace : how does peace education differ from ‘normal’ schooling?

This article reviews literature on the roles of schooling in both reproducing and actively perpetrating violence, and sets out an historical explanation of why schools are socially constructed in such a way as to make these roles possible. It then discusses notions of peace education in relation to one particular project in England before using empirical data from research on the project to examine contrasts between peace education approaches and ‘normal’ schooling from the viewpoints of project workers, pupils and teachers. It concludes that such contrasts and tensions do indeed exist and that this raises serious questions about the compatibility of peace education and formal schooling

Democratic citizenship education: Towards a model for establishing democratic mathematics teacher education

This article provides an explication of the concepts of democracy and democratic citizenship from a political dimension, it also offers insight into the nature of democracy and democratic citizenship in post-apartheid South Africa. The article further outlines the relationship between mathematics and democracy, as well as a number of pedagogical approaches which are capable of fostering democratic principles in mathematics education classrooms. Finally, the article proposes a model which encompasses a trilogy of democratic principles; humanising pedagogy; and social, cultural, economic and political issues which can be employed in preparing mathematics student teachers to become fully democratic citizens. &nbsp

Normal-superfluid interaction dynamics in a spinor Bose gas

Coherent behavior of spinor Bose-Einstein condensates is studied in the presence of a significant uncondensed (normal) component. Normal-superfluid exchange scattering leads to a near-perfect local alignment between the spin fields of the two components. Through this spin locking, spin-domain formation in the condensate is vastly accelerated as the spin populations in the condensate are entrained by large-amplitude spin waves in the normal component. We present data evincing the normal-superfluid spin dynamics in this regime of complicated interdependent behavior.Comment: 5 pages, 4 fig

Abstract P119: Non-exercise Cardiorespiratory Fitness Prediction Equations: Accuracy Over Time in Apparently Healthy Adults

Mortality risk predictions are improved with routine assessment of cardiorespiratory fitness (CRF). Accordingly, an American Heart Association Scientific Statement suggests routine clinical assessment of CRF in apparently healthy adults minimally using non-exercise prediction equations, which can be calculated from common health metrics. However, no study has assessed the ability of non-exercise CRF prediction equations to accurately detect longitudinal changes

Spatial Resolution of Spin Waves in an Ultra-Cold Gas

We present the first spatially resolved images of spin waves in a gas. The complete longitudinal and transverse spin field as a function of time and space is reconstructed. Frequencies and damping rates for a standing-wave mode are extracted and compared with theory

Change in Metabolic Syndrome and Cardiorespiratory Fitness Following Exercise Training – The Ball State Adult Fitness Longitudinal Lifestyle Study (BALL ST)

This observational cohort study indicates an inverse relationship between the change in CRF and the change in MetS severity following exercise training. These results suggest that participation in a community-based exercise program yields significant improvements in CRF, MetS risk factors, the prevalence of the binary MetS, and the MetS severity score. Improvement in CRF through exercise training should be a primary prevention strategy for MetS