Upcoming Events For Colloquia

Wed Aug 23, 2017

Physics Colloquium: Prof. Neil Johnson, University of Miami

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

In this talk, I will try to convince you that buried in arguably the most urgent challenge facing society, i.e. global terrorism, lies a wealth of interesting physics related to many-body out-of-equilibrium systems, complex dynamical networks, critical phenomena, kinetic theory, and even Green's Functions and Feynman diagrams [1-10]. Moreover there now exist detailed spatiotemporal datasets on global violent events which back up these claims. During the talk, I will try to emphasize the point that this is not just about providing something new for Physics, but rather that Physics is uniquely positioned to offer key insights into this important ‘many-person problem’ in a way that the traditional disciplines associated with analyzing terrorism can never do.

Posted In: Colloquia

Wed Aug 30, 2017

Physics Colloquium: Prof. Tom McLeish, Durham University

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

There is a fruitful and developing programme exploring analogies between evolution and the statistical mechanics of complex matter [1,2].  Both treat exponentially large spaces of configurations (possible genomes/possible microstates) which is explored by stochastic dynamics (random mutation/thermal motion).  Both admit maximisation/minimisation criteria (fitness/free-energy).  There are even evolutionary analogies of temperature (inverse population size) [3]  and free energy (“free fitness”) [4]. 

     Beneath the notion of thermodynamic equilibrium is the assumption of ‘ergodicity’ -  the exploration of configuration space in a representative way, with an induced characteristic timescale to attain equilibrium.  ‘Ergodic times’ are typically much less than the exponentially long times required for a complete search.  For example, for a polymer of N subunits, the timescale for equilibration increases as N2 rather than the zN of a complete search.  The strong dependence of these timescales on system size means that, even if a large system is not in equilibrium, some of its subsystems may be.  We consider an illustrative example of the insect compound eye, which also carries the advantage that its optimum (in acuteness of vision) relies on physics and can be calculated [5].

     The ergodic exploration of systems and subsytems within evolution generates a discussion of timescales for representative exploration of genotypic spaces.  This in turn suggests a strong connection to the phenomenon of convergent evolution, and the conjecture that this might be expected in subsystems whose fitness is optimised by well-defined phenotypical constraints, and whose ergodic time is less than the relevant evolutionary time. 

 

[1] R.A. Fisher, Trans. Roy. Soc. Edinb., 52, 399-433.

[2] N.H. Barton and J.B. Coe, J.Theor. Biol. 259, 317–324 (2009).

[3] G. Sella and Hirsh AE, Proc Natl Acad Sci USA, 102, 9541–9546. (2005).

[4]  B.S. Khatri, T.C.B. McLeish and R.P. Sear, PNAS, 106, 9564-9569 (2009).

[5] T.C.B. McLeish, J. Roy. Soc. Interface Focus, 20150041 (2015).

Posted In: Colloquia

Wed Sep 6, 2017

Physics Colloquium: Dr. Christopher Wesselborg, Managing Editor, Physical Review C

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

Title TBA

Dr. Christopher Wesselborg
Managing Editor of Physical Review C…

Posted In: Colloquia

Wed Sep 13, 2017

Colloquium: Graduate Physics Conference Talks

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

Annual Graduate Physics Students Research Conference

Details forthcoming

Posted In: Colloquia and Special Lectures and Events

Wed Sep 20, 2017

Physics Colloquium: Prof. Jorge A. Lopez

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

The matter in the outermost layer, or “crust,” of a neutron star (the remnant of a supernova) is believed to host a variety of phases in which dense regions of nucleons are filled with voids of lower density. The presence of the phases, euphemistically referred to as “nuclear pasta” because of their resemblance to the shapes of lasagna, gnocchi, and spaghetti, may affect the emission of neutrinos, the primary mechanism by which the neutron star cools. In this work, molecular dynamics and a set of topological and geometric descriptors (volume, area, mean curvature, and its Euler characteristic—a number that represents the phase’s topology) are used to accurately identify the pasta phases predicted by dynamical simulations, a labeling scheme that could be used to directly map the shape of a pasta phase to its effect on neutrino emission and neutron star cooling.

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Mon Sep 25, 2017

Special Colloquium: Prof. Lisa Randall, Harvard University

4:00 PM - 5:00 PM
123 Nieuwland Science Hall

Title TBA

Lisa Randall
Frank B. Baird, Jr., Professor of Science  
Harvard University…

Posted In: Colloquia and Special Lectures and Events

Wed Sep 27, 2017

Physics Colloquium: Prof. Saurabh Jha, Rutgers University

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

Title TBA

Prof. Saurabh Jha
Professor of Physics and Astronomy
Rutgers, the State University of New Jersey…

Posted In: Colloquia

Wed Oct 4, 2017

Physics Colloquium: Dr. Geoffrey Grinyer, University of Regina

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

Title TBA

Dr. Geoffrey Grinyer
University of Regina…

Posted In: Colloquia

Wed Oct 25, 2017

Physics Colloquium/Miller Endowed Lecture: Prof. Rocky Kolb, University of Chicago

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

The big bang is a laboratory to explore the properties of particles that cannot be explored at terrestrial laboratories. In addition to thermal production of new particles, there is another source of cosmological particle production. In 1939 Edwin Schrödinger pointed out that particle-antiparticle pairs could be created merely by the violent expansion of space. The spontaneous appearance of particles from the vacuum so disturbed Schrödinger that he referred to it as an “alarming phenomenon.” The phenomenon is now thought to be the origin of density fluctuations produced in inflation as well as a background of gravitational waves. Gravitational particle production is a rich phenomenon, which continues to be explored.

Posted In: Colloquia and Special Lectures and Events

Wed Nov 8, 2017

Physics Colloquium: Prof. Albert Young

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

Title TBA

Prof. Albert Young
North Carolina State University…

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Wed Dec 6, 2017

Physics Colloquium: Prof. Kumar S. Sharma

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

Title TBA

Professor Kumar S. Sharma
Department of Physics and Astronomy
University of Manitoba…

Posted In: Colloquia