Open Access. Powered by Scholars. Published by Universities.®

Physics Commons

Open Access. Powered by Scholars. Published by Universities.®

PDF

Physics - All Scholarship

Series

Atomic physics

Publication Year

Articles 1 - 2 of 2

Full-Text Articles in Physics

Multiple Transient Memories In Experiments On Sheared Non-Brownian Suspensions, Joseph Paulsen, Nathan C. Keim, Sidney R. Nagel Jan 2014

Multiple Transient Memories In Experiments On Sheared Non-Brownian Suspensions, Joseph Paulsen, Nathan C. Keim, Sidney R. Nagel

Physics - All Scholarship

A system with multiple transient memories can remember a set of inputs but subsequently forgets almost all of them, even as they are continually applied. If noise is added, the system can store all memories indefinitely. The phenomenon has recently been predicted for cyclically sheared non-Brownian suspensions. Here we present experiments on such suspensions, finding behavior consistent with multiple transient memories and showing how memories can be stabilized by noise.


Energy-Dependent Ps-He Momentum-Transfer Cross Section At Low Energies, J. J. Engbrecht, M. J. Erickson, C. P. Johnson, A. J. Kolan, A. E. Legard, S. P. Lund, M. J. Nyflot, J. D. Paulsen Jan 2008

Energy-Dependent Ps-He Momentum-Transfer Cross Section At Low Energies, J. J. Engbrecht, M. J. Erickson, C. P. Johnson, A. J. Kolan, A. E. Legard, S. P. Lund, M. J. Nyflot, J. D. Paulsen

Physics - All Scholarship

Positronium (Ps)-He scattering presents one of the few opportunities for both theory and experiment to tackle the fundamental interactions of Ps with ordinary matter. Below the dissociation energy of 6.8 eV, experimental and theoretical work has struggled to find agreement on the strength of this interaction as measured by the momentum-transfer cross section (Ïm). Here, we present work utilizing the Doppler broadening technique with an age-momentum correlation apparatus. This work demonstrates a strong energy dependence for this cross section at energies below 1 eV and is consistent with previous experimental results.