(2 p.m. - 3 p.m.)

**Vadim Zharnitsky**

**Department of Mathematics **

**University of Illinois at Urbana-Champaign**

**Hamiltonian dynamics in the linear search problem**

The linear search problem was introduced by Beck and Bellman in the early 60s. Assume an object is hidden on the real line according to a known probability distribution. The searcher wishes to find this object in the minimal expected time. What is the optimal search path? We study this problem from the view point of Hamiltonian dynamics. For the specific, yet, representative case of exponential distribution, it is shown that the optimal path follows an unstable separatrix in the associated Hamiltonian system. Higher dimensional generalization will be also discussed. This is a joint work with Yuliy Baryshnikov.

Prior to the colloquium, coffee will be served in FO 2.404

Sponsored by the Department of Mathematical Sciences

]]>(3:30 p.m. - 4:30 p.m.)

**Dr. Devin McPhillips is a candidate for the faculty position in the Department of Geosciences in the field of Neotectonics. Dr. McPhillips will be giving a lecture on Friday, March 27, 2015 at 3:30 p.m. in ROC 2.103. The title of his presentation will be "Tectonics topography and erosion in the Sierra Nevada". **

**Admission is free and refreshments will be served after the lecture in ROC 2.107. We hope you will plan to attend. **

(4 p.m. - 5 p.m.)

How can we solve the national debt crisis? Is it a good idea to take on a student loan? Is it safe to talk on a cell phone while driving? Are there viable energy alternatives to fossil fuels? What could you do with a billion dollars? Could simple policy changes reduce political polarization? These questions may seem very different, but they all share two things in common. First, they all concern important topics that can be understood only with clear quantitative or mathematical thinking. Second, they are all topics that, at least traditionally, have been noticeably absent from the standard mathematics curriculum. This presentation will offer a series of examples of this disconnect, along with suggestions on how to rectify it and improve mathematics education.

*Astrophysicist, author, and educator Jeffrey Bennett’s extensive experience includes teaching at every level from preschool through graduate school, proposing and helping to develop the Voyage Scale Model Solar System on the National Mall in Washington, DC and serving two years as a Visiting Senior Scientist at NASA Headquarters, where he helped create numerous programs designed to build stronger links between the research and education communities.*

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(7 p.m. - 8 p.m.)

This year (2015) marks the 100th anniversary of Einstein's completion of his General Theory of Relativity, yet the vast majority of students, teachers, and the public know very little about the critical importance of either the special or general theories to modern understanding of the universe. In this presentation, based on his book What is Relativity? from Columbia University Press, Dr. Bennett will introduce you to the basic ideas of Einstein's theories and discuss why they are important to everyone. (He’ll also help you understand the movie Interstellar.) No prior knowledge of physics or relativity will be assumed.

*Astrophysicist, author, and educator Jeffrey Bennett’s extensive experience includes teaching at every level from preschool through graduate school, proposing and helping to develop the Voyage Scale Model Solar System on the National Mall in Washington, DC and serving two years as a Visiting Senior Scientist at NASA Headquarters, where he helped create numerous programs designed to build stronger links between the research and education communities.*

(4 p.m. - 5:15 p.m.)

Dr. Michael Kesden (UT Dallas)

Generic binary black holes have spins that are misaligned with their orbital angular momentum. I will derive an effective potential for binary black-hole spin precession with which I can solve the orbit-averaged spin-precession equations analytically for arbitrary mass ratios and spins. These solutions are quasiperiodic functions of time: after a precessional period the spins return to their initial relative orientations. They classify black-hole spin precession into three distinct morphologies between which the black holes can transition during their inspiral. They also can be used to derive a precession-averaged evolution equation that can be numerically integrated on the radiation-reaction time, allowing black-hole spins to be tracked statistically from formation to merger. This new equation can be used to predict the signatures of black-hole formation in the gravitational waves emitted near merger and the distributions of final spins and gravitational recoils.

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