James Hansen Nasa Climate Expert in Claremont

posted on January 29, 2013 by

James Hansen (renowned physicist, head of NASA Goddard Institute for Space Studies, best known for uncompromising stance on curbing global greenhouse gas emissions) will be speaking at Pilgrim Place on the evening of Sunday, February 17, and also has agreed to give a master class at Pomona College on the morning of Monday, February 18 from 9:00-10:15am in Rose Hills Theater.

Quantum Turbulence in Flatland

posted on January 29, 2013 by

Brian Anderson, University of Arizona

Turbulent fluid flows are found throughout nature, and studied in numerous disciplines, yet a deep physical understanding of the nature of turbulence stubbornly remains “the most important unsolved problem of classical physics” [attributed to Feynman].  But turbulence is not just a classical phenomenon: it has long been studied in superfluid helium, where quantum mechanics and the presence of quantized vortices offer simplifications to characterizing turbulent flows.  Nevertheless, the nature of turbulence still remains elusive.   For two-dimensional (2D) flows in quantum fluids, however, there are significant prospects for the development of a clear understanding of the relationships between statistical signatures of turbulence, microscopic dynamics of quantum vortices, and other elements of turbulence. In this talk, I will discuss the study of 2D quantum turbulence in atomic Bose-Einstein condensates (BECs), beginning with introductions to the fascinating worlds of two-dimensional turbulence, vortices, and BECs. I will then focus on recent experimental research at the University of Arizona, and associated numerical and theoretical work, investigating 2D quantum turbulence and vortex dynamics in BECs.  Although we remain far from a full understanding of turbulence, it is hoped that these studies of 2D quantum turbulence in BECs may shed important new light on at least this one interesting facet of turbulence.