**Today @ Colorado State has been replaced by SOURCE. This site exists as an archive of Today @ Colorado State stories between January 1, 2009 and September 8, 2014.**

April 12, 2010

The Department of Mathematics at Colorado State is hosting the annual Arne Magnus Lecture Series on Wednesday, April 14 and Thursday, April 15. This year's guest speaker is Professor Gunther Uhlmann, the Walker Family Endowed Professor of Mathematics at the University of Washington. All lectures are free and open to the public.

Professor Gunther Uhlmann

Arne Magnus Lecture Series

Thursday, April 15, 3-4 p.m.

130 Glover Building

The Department of Mathematics at Colorado State is hosting the annual Arne Magnus Lecture Series on Wednesday, April 14 and Thursday, April 15. This year's guest speaker is Professor Gunther Uhlmann (*photo at right*), the Walker Family Endowed Professor of Mathematics at the University of Washington.

Professor Gunther Uhlmann will present a public lecture on Thursday, April 15 at 3-4 p.m. in 130 Glover Building. The title is, "Cloaking, Invisibility and Inverse Problems."

We describe recent theoretical and experimental progress on making objects invisible to detection by electromagnetic waves, acoustic waves and quantum waves. For the case of electromagnetic waves, Maxwell's equations have transformation laws that allow for design of electromagnetic materials that steer light around a hidden region, returning it to its original path on the far side.

Not only would observers be unaware of the contents of the hidden region, they would not even be aware that something was being hidden. The object, which would have no shadow, is said to be cloaked.

We recount the recent history of the subject and discuss some of the mathematical issues involved.

Please join Professor Uhlmann at a reception following his lecture in 117 Weber. The Arne Magnus Lectures are given annually in the Department of Mathematics at Colorado State University in honor of Professor Arne Magnus, our friend and colleague for 25 years.

The invisibility cloaking means coating of an object with a special material so that light goes around the object. *Courtesy of Uhlmann's website*.

Wednesday, April 14, 4-5 p.m.

Hammond Auditorium, 120 Engineering

Calderón's problem consists in finding the electrical conductivity of a medium by making voltages and current measurements at the boundary. In mathematical terms one tries to determine the coefficient of a partial differential equation by measuring the corresponding Dirichlet-to-Neumann map.

This problem arises in geophysical prospection and it has been proposed as a diagnostic tool in medical imaging, particular early breast cancer detection. We will also describe the progress that has been made on this problem since Calderón's seminal paper in 1980.

*Prior to the seminar, please join Uhlmann and the Department of Mathematics for coffee in Weber 117 at 3:30 p.m.*

Thursday, April 15, 11-12 p.m.

Hammond Auditorium, 120 Engineering

Metamaterials can in theory be used for building an artificial electromagnetic wormhole. It is constructed by coating a hollow cylinder with metamaterial. *Courtesy of Uhlmann*'s* website*.

In this lecture we will describe a surprising connection between Calderón's inverse problem and travel time tomography. This latter problem consists in determining the index of refraction (sound speed) of a medium by measuring the travel times of sound waves going though the medium.

In mathematical terms the question is to determine the Riemannian metric of a Riemannian manifold with boundary by measuring the distance function between points on the boundary. In differential geometry this is known as the boundary rigidity problem.

This inverse problem arises in geophysics in determining the inner structure of the Earth by measuring the travel times of seismic waves as well as in ultrasound imaging.

*Prior to the seminar, please join Uhlmann and the Department of Mathematics for coffee in Weber 117 at 10:30 a.m.*

The 2010 lectures are supported by the Arne Magnus Lecture Fund and the Albert C. Yates Endowment in Mathematics. All lectures are free and open to the public.

Contact: Christie Franklin

E-mail: franklin@math.colostate.edu

Phone: (970) 491-6452

- 2567
- Print this Story
- Posted in Events