主讲人：Bjarke Guadnason教授（日本庆应大学）

Title：

1) Boundary charges for solitons,

2) Vortex equations in anN=2 U(1)^M model,

3) Vibrational spectra of solitons, and

4) The mass gap problem of Yang-Mills theory"

Abstract:

This talk will contain four parts:

1) A brief introduction to the concepts of newly found boundary charges; they are integral identities and can be viewed as a generalization of the well-known Pohozaev identity. Apart from being mathematically interesting, they may in principle be used to extract non-perturbative information from physical systems.

2) Vortex equations in an extended supersymmetric model with M U(1) gauge groups and a charge matrix are studied. Interesting alignment between the Fayet-Iliopoulos parameters and the orientation of the vortex equations in SU(2)_R space is revealed. The relation in turn depends on the winding numbers in each gauge group.

3) Considerations in the Skyrme model of 3-dimensional solitons that are solutions to nonlinear PDEs show that a semiclassical approach to  reproducing nuclear masses is impossible unless the quantization method is extended from rigid body quantization to including low-lying but massive modes of the solutions. Representation theory classifies the vibrational modes and the spin they can contribute to is in turn a result purely of representation theory.

4) The mass gap problem of Yang-Mills theory is briefly discussed.

时间（Tentative）： 7月24日9:00-12:00

地点：学院一楼报告厅