Department of Physics

Fall 2005 | Spring 2006 | Fall 2006 | Spring 2007 | Fall 2007 | Spring 2008 | Fall 2008 | Spring 2009 | Fall 2009 | Spring 2010 | Fall 2010 | Spring 2011 | Fall 2011 | Spring 2012 | Fall 2012 | Spring 2013 | Fall 2013 | Spring 2014

Colloquia & Seminars, Fall 2010

-------------------------

 

A Modified Split-Hopkinson Pressure Bar

Speaker: Aaron Schye
Date: September 3, 2010 (Friday)
Time: 4 p.m.
Room: 205 Currens Hall

Abstract
The conventional split-hopkinson pressure bar was modified to increase transmitted strain and improve signal quality when testing plastic materials. This was accomplished by replacing the solid transmitted bar with a hollow bar of equivalent diameter and length. Bar-to-bar tests using the conventional set-up were done to calibrate the apparatus and deduce the proper dispersion correction parameters. Polyurea, a shock absorbing material, was tested after the dispersion correction was adequately performed on the bar-to-bar data. The polyurea sample was then tested after implementation of the hollow transmitted bar. The results of the hollow bar test were compared to solid bar test and show that transmitted strain has doubled in the modified set-up. However, the geometry of the hollow bar caused difficulties in the dispersion correction and the signals could not be reconstructed as accurately as with the solid bar.

About the speaker:
Aaron Schye is a second year graduate student of physics at Western Illinois University.

-------------------------

 

Brief Introduction to Quantum Information Processing

Speaker: Professor Kishor T. Kapale
Date: September 10, 2010 (Friday)
Time: 4 p.m.
Room: 205 Currens Hall

Abstract
I will give a very basic introduction to the paradigms of quantum information processing without assuming any knowledge of the subject. Further, I will discuss strategies for realistic physical implementations of quantum information processing tasks. I will also mention some of my own research in the quantum information and related areas towards the end.

About the speaker:
Professor Kishor Kapale is a physics professor from the Department of Physics, Western Illinois University. Professor Kapale is a theoretical physicist whose research focuses on quantum optics, atomic optics, quantum information theory and applied quantum physics.

-------------------------

 

Brief Introduction to Quantum Information Processing -II

Speaker: Professor Kishor T. Kapale
Date: September 17, 2010 (Friday)
Time: 4 p.m.
Room: 205 Currens Hall

Abstract
I will revisit the most important concepts covered in the last week's colloquium. Then I will pick up where I left off and discuss concepts of quantum teleportation and its physical implementations and basic elements of quantum computing. I will briefly mention some of my own research in the quantum information and related areas towards the end.

About the speaker:
Professor Kishor Kapale is a physics professor from the Department of Physics, Western Illinois University. Professor Kapale is a theoretical physicist whose research focuses on quantum optics, atomic optics, quantum information theory and applied quantum physics.

-------------------------

 

Mesoscopic light transport properties of a single biological cell: Early detection of cancer

Speaker: Dr. Prabhakar Pradhan
Date: September 24, 2010 (Friday)
Time: 4 p.m.
Room: 205 Currens Hall

Abstract
We have developed a mesoscopic partial wave spectroscopy (PWS) technique to measure the nanoscopic light transport properties of weakly disordered mesoscopic photonic systems such as biological cells. Using mesoscopic approach, we have statistically quantified the light reflection coefficient and its correlation due to nanoscale refractive index fluctuations within a biological cell, and the results are consistent with the prediction of mesoscopic/nanoscopic light transport theory. Finally, using these parameters, we have imaged and quantified the nanoscale optical disorder strength within the biological cell. Results of precancerous cell studies and cancer detection by the technique will be discussed.

About the speaker:
Dr. Prabhakar Pradhan is a Research Assistant Professor in the Departments of Biomedical Engineering in the Robert R. McCormick School of Engineering and Applied Science at Northwestern University, Evanston, IL. Dr. Pradhan did his Ph.D. at Indian Institute of Science, Bangalore, India, in Condensed Matter Physics. Before joining Northwestern, he was a post-doctoral researcher at University of California - Los Angeles, CA and a visiting researcher at the Massachusetts Institute of Technology, Cambridge, MA. His current research focuses mainly in the area of experimental biophotonics/nano-biophotonics.

-------------------------

 

Laser-assisted electron impact autoionization of Helium

Speaker: Professor Bruno deHarak
Date: October 1, 2010 (Friday)
Time: 4 p.m.
Room: 205 Currens Hall

Abstract
This talk will discuss our attempts to perform the experiments to examine electron impact autoionization in the presence of a laser field. Although electron-impact ionization in the presence of a laser field was discussed as long ago as 1988, the first experimental results, by Höhr and her collaborators, were not published until 2005. Those experiments found statistically significant differences in the direct ionization process for the field free (laser off) and field assisted (laser on) cases. The results were in poor agreement with quantum calculations but could be described using a simple classical model. Instead of observing direct ionization, our intent is to examine autoionization. The chief advantage of this is that autoinizing resonances provide energy markers - the absorption and emission of photons should then result in the presence of sidebands in the energy spectrum. Details of our experimental apparatus, and a progress report on these experiments will be provided.

About the speaker:
Professor Bruno DeHarak is a Physics Professor at the Departments of Physics, Illinois Wesleyan University. His current research focuses on the use of ultrafast electron diffraction to study the breakup of simple molecules.

-------------------------

 

Investigating the Earliest Phases of Massive Star Formation

Speaker: Professor Esteban Araya
Date: November 12, 2010 (Friday)
Time: 4 p.m.
Room: 205 Currens Hall

Abstract
Massive stars--stars with more than eight times the mass of the Sun--are responsible for the enrichment of the interstellar medium with heavy elements and the existence of extraordinary physical objects such as neutron stars and black holes. In this talk, I will review some of our current work on the study of massive star formation. In particular, the formation of massive stars within molecular filaments and the discovery of periodic maser flares of formaldehyde and methanol molecules, which could be caused by periodic accretion events onto young massive binaries.

About the speaker:
Professor Esteban Araya is a physics professor from the Department of Physics, Western Illinois University. His research focuses on the study of massive star formation and the interstellar medium. He carries out observations at radio frequencies with some of the most sophisticated radio telescopes.