Type: Seminar

Distribution: World

Expiry: 9 Oct 2009

Auth: carberry(.pmstaff;1014.2002)@p723.pc.maths.usyd.edu.au

This Friday October 9 at 2pm Prof. Zdzislaw Brzezniak (York. U.K.) will speak at the Joint Colloquium at Sydney Uni. Details of his talk titled "Stochastic Landau-Lifschitz-Gilbert Equation" are below. If you would like to lunch with the speaker, meet outside Carslaw Building at 12.30PM. ___________________JOINT COLLOQUIUM______________________ Speaker: Prof. Zdzislaw Brzezniak (York. U.K.) Title: Stochastic Landau-Lifschitz-Gilbert Equation Date: Friday, October 9, 2009 Time: 2:00 pm Venue: Room 275 Carslaw Building, University of Sydney Abstract: In this talk we will consider the three-dimensional Landau-Lifshitz-Gilbert equation perturbed by a multiplicative space-dependent noise. This equation, fundamental for the theory of magnetic memories, describes evolution of spins in ferromagnetic materials under the influence of thermal noise. The necessity to include the thermal noise in the equation was observed by Physicists in the early fifties but the rigorous mathematical theory was missing. Since the physical theory prescribes the fixed length of the spin vectors, any solution must take values in the sphere. This fact leads to interesting connections of this equation with the equation for the flow of harmonic maps. We show the existence of weak martingale solutions taking values in a sphere and discuss regularity of solutions. We will sketch proof of the existence of solutions and formulate some open problems. This is a joint work with Ben Goldys and Terry Jegaraj (both UNSW Sydney). Enquiries to Emma Carberry,carberry@maths.usyd.edu.au, 9351 3796 or Brian Jefferies, 0458 8882544, b.jefferies@unsw.edu.au