Radiations Newsletter

Fall Term 2020 Week 1

Hi, Physics folks!

Please join the faculty and staff for a zoom welcome to the department and term.  You don’t know how sad we are that we can’t do it over monstrous amounts of pizza like we normally would!  We’ll still do some introductions, though, and would love to hear something about your summer.

Visiting Professor of Physics Rajarshi Roy from UMD will give the talk “Seeing the Light:  Photons, Complexity, and Randomness”.

It will be on Thursday, September 17th at 10:50 am Central time.  Zoom link

Abstract:

Seeing the light is no simple task – it is accomplished with a complex system consisting of our eyes and brain, which we are only beginning to understand in a rudimentary way. This is certainly good news – there is so much interesting science left to do and so many interesting discoveries to make, experimentally and theoretically. We will look at a few examples to illustrate these points, the highly interdisciplinary nature of the problems, and tools needed to begin to unravel them. Light conveys information at multiple scales of space and time, and through multiple variables. We will explore how we have learned to extract information from light over the ages, first with our eyes and brain, and then through the use of different detectors that sense the dynamics of light (waves and photons) in ever more sensitive and delicate ways.

As new light sources and detectors have been developed, we have learned how order and disorder can both be useful and how we can learn to control both the temporal and spatial coherence of light. We find that entropy and information measures depend on the scales of detection and measurement, and our perception of what is deterministic chaos and what is noise is governed by the precision and time scale of our observations. We will describe experiments to probe the transition from randomness to determinism in a simple optical feedback system, entropy production and random number generation. Finally, we describe a new form of chaotic dynamics, observed recently in optoelectronic systems, that is named “laminar” chaos to distinguish it from the traditionally studied “turbulent” chaos. This type of dynamics – characterized by irregularly spaced steady states of periodic duration and separated by rapid transitions – occurs in systems with variable time-delays. Laminar chaos could have novel applications in information processing.

All seniors should attend this meeting!  If you are a junior who has decided that you’d like to do your comps this year, you should *also* attend this meeting!

Various faculty and staff members will be joining in to talk about not just comps, but careers, letters of recommendation, and other things you’re going to want and need to know.  If you can NOT attend, please let Trenne know and we’ll figure out the best way to get all the needed info to you.

It will take place on Wednesday, Sept. 23rd at 4:30 pm.   Zoom link