Upcoming Colloquia

Wednesday, October 14

4:00 PM, C215 ESC

Gus Hart

Department of Physics and Astronomy, BYU

French Fries or Onion Rings? Improving integration in DFT calculations

Our group has spent hundreds of millions of cpu hours calculating the energies of different materials and their competing structures. The energy of the occupied electron states is a small part of the total energy of a given material, but calculating electron energy accounts for almost all of the numerical error in these calculations (at least in metals). Current methods of integrating these "electron band energies" are very high-fat (take lots of computer time), but they are deliciously simple. We are testing ideas to increase convergence rates in these integrals. One of our low-fat ideas is to discretize the integration, at least conceptually, as "onion rings" instead of "french fries." (You didn't know onion rings were low-fat?!) I'll describe the basic physics of band structure, the fundamentals of numeric integration, describe the "onion rings" idea (and some other sugar-free things we implemented), and convince you that this problem is so important, and so interesting, that you should forget your research and help us figure it out.

Wednesday, October 21

4:00 PM, C215 ESC

Andrew Piacsek

Physics Department, Central Washington University

Bang! Boom. Puff? The Science of Quiet Supersonic Aircraft

The technology of supersonic flight is more than 60 years old, yet there are currently no commercial aircraft that fly faster than the speed of sound.  The barrier, of course, is the sonic boom, which is a weak shock wave that is created by any object moving through a fluid faster than the local sound speed.  After reviewing the basic physics underlying the formation and propagation of sonic booms, I will provide an overview of six decades of research into the problem of mitigating their annoyance on the ground, including ongoing efforts to modify aircraft in order to "shape" the boom.  I will also present some of my own research on modeling focused booms and the effects of turbulence.  The promising results of shaping sonic booms suggest that commercial supersonic transport may be just around the corner.

Wednesday, October 28

4:00 PM, C215 ESC

David Richards

Lawrence Livermore National Laboratory

Wednesday, November 4

4:00 PM, C215 ESC

Wednesday, November 11

4:00 PM, C215 ESC

Kirk F. Sorensen

President, Flibe Energy

Wednesday, November 18

4:00 PM, C215 ESC

John Shumway

Computational Scientist, Stone Ridge Technology

Wednesday, December 2

4:00 PM, C215 ESC

Corinne Manogue

Dept of Physics, Oregon State University

Wednesday, December 9

4:00 PM, C215 ESC

J. Ward Moody

Dept of Physics & Astronomy, BYU

We welcome anyone who wish to attend, and typically serve refreshments ten minutes before the colloquium begins. Speakers generally keep their presentation accessible to undergraduate physics students.