| We investigate the topological defects in supersymmetry. The amazing characteristics of the BPS states is that they preserve a part of the supersymmetry, which ensures the cancellation between the divergences of fermion and boson. BPS saturated domain walls are the important type of the topological defects because of the idea that the matter in our world is made of the zero modes trapped on the surface of a 1 + 3 dimensional domain wall embedded in a higher-dimensional universe. We investigate the BPS properties of the wall-like topological defects on the cylinder, which is related to the compactified extra dimensions. We also study the BPS property of the Abrikosov-Nielsen-Olesen string (vortex) in the N = 2 supersymmetric QED. We also investigate an interesting behavior of the gravity in the model where our four dimensional world is a wall-like brane embedded in a space with two or more infinite volume extra dimensions. |
