QG guest seminar.
Speaker: Kentaroh Yoshida.
Title: "Chaotic Instability in the BFSS matrix model".

Recently, chaotic scattering has been studied in the context of String
Theory. Chaotic scattering occurs when the particle motion in a
scattering region cannot be exactly solved. This is a more general
situation than the familiar solvable scattering problems. In this talk,
as a simple example, we first introduce chaotic scattering in a
four-hill potential model and then present self-similar structures
(fractals) appearing in the initial value space and the Cantor set in
the time delay function. A method for calculating the fractal dimension
is also explained. Then we discuss chaotic scattering in the
Banks-Fischler-Shenker-Susskind (BFSS) matrix model, which is a
non-perturbative formulation of a superstring theory. This model can also
be interpreted as a matrix regularization of a supermembrane theory, in
which the basic degrees of freedom are membranes. The potential of this
model has flat directions, which are related to the instability of the
supermembrane theory. We investigate classical motions of a spherical
membrane and show that this instability can be regarded as chaotic
scattering.