Loading a vapor cell magneto-optic trap using light-induced atom desorption

Low intensity white light was used to increase the loading rate of $^{87}$Rb atoms into a vapor cell magneto-optic trap by inducing non-thermal desorption of Rb atoms from the stainless steel walls of the vapor cell. An increased Rb partial pressure reached a new equilibrium value in less than 10 seconds after switching on the broadband light source. After the source was turned off, the partial pressure returned to its previous value in $1/e$ times as short as 10 seconds.Comment: 7 pages, 6 figure

Dynamics of evaporative cooling in magnetically trapped atomic hydrogen

We study the evaporative cooling of magnetically trapped atomic hydrogen on the basis of the kinetic theory of a Bose gas. The dynamics of trapped atoms is described by the coupled differential equations, considering both the evaporation and dipolar spin relaxation processes. The numerical time-evolution calculations quantitatively agree with the recent experiment of Bose-Einstein condensation with atomic hydrogen. It is demonstrated that the balance between evaporative cooling and heating due to dipolar relaxation limits the number of condensates to 9x10^8 and the corresponding condensate fraction to a small value of 4% as observed experimentally.Comment: 5 pages, REVTeX, 3 eps figures, Phys. Rev. A in pres

Natural Orbitals and BEC in traps, a diffusion Monte Carlo analysis

We investigate the properties of hard core Bosons in harmonic traps over a wide range of densities. Bose-Einstein condensation is formulated using the one-body Density Matrix (OBDM) which is equally valid at low and high densities. The OBDM is calculated using diffusion Monte Carlo methods and it is diagonalized to obtain the "natural" single particle orbitals and their occupation, including the condensate fraction. At low Boson density, $na^3 < 10^{-5}$, where $n = N/V$ and $a$ is the hard core diameter, the condensate is localized at the center of the trap. As $na^3$ increases, the condensate moves to the edges of the trap. At high density it is localized at the edges of the trap. At $na^3 \leq 10^{-4}$ the Gross-Pitaevskii theory of the condensate describes the whole system within 1%. At $na^3 \approx 10^{-3}$ corrections are 3% to the GP energy but 30% to the Bogoliubov prediction of the condensate depletion. At $na^3 \gtrsim 10^{-2}$, mean field theory fails. At $na^3 \gtrsim 0.1$, the Bosons behave more like a liquid $^4$He droplet than a trapped Boson gas.Comment: 13 pages, 14 figures, submitted Phys. Rev.

Highly-parallelized simulation of a pixelated LArTPC on a GPU

The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

Key Learning Statements for persistent pain education: an iterative analysis of consumer, clinician and researcher perspectives and development of public messaging

Over the last decade, the content, delivery and media of pain education have been adjusted in line with scientific discovery in pain and educational sciences, and in line with consumer perspectives. This paper describes a decade-long process of exploring consumer perspectives on pain science education concepts to inform clinician-derived educational updates (undertaken by the authors). Data were collected as part of a quality audit via a series of online surveys in which consent (non-specific) was obtained from consumers for their data to be used in published research. Consumers who presented for care for a persistent pain condition and were treated with a pain science education informed approach were invited to provide anonymous feedback about their current health status and pain journey experience 6, 12 or 18 months after initial assessment. Two-hundred eighteen consumers reported improvement in health status at follow-up. Results of the surveys from three cohorts of consumers that reported improvement were used to generate iterative versions of 'Key Learning Statements'. Early iteration of these Key Learning Statements was used to inform the development of Target Concepts and associated community-targeted pain education resources for use in public health and health professional workforce capacity building initiatives. Perspective This paper reflects an explicit interest in the insights of people who have been challenged by persistent pain and then recovered, to improve pain care. Identifying pain science concepts that consumers valued learning provided valuable information to inform resources for clinical interactions and community-targeted pain education campaigns.Hayley B. Leake, Amelia Mardon, Tasha R. Stanton, Daniel S. Harvie, David S. Butler, Emma L. Karran, Dianne Wilson, JohnBooth, Trevor Barker, Pene Wood, Kal Fried, Chris Hayes, Lissanthea Taylor, Melanie Macoun, Amanda Simister, G. Lorimer Moseley, Carolyn Berryma

Redefining phenotypes to advance psychiatric genetics: Implications from hierarchical taxonomy of psychopathology

Stress and Psychopatholog