摘要
We study the null bulk geodesic motion in the brane world in which the bulk metric has an un-stabilizedextra spatial dimension. We find that the null bulk geodesic motion as observed on the 3-brane with Z2 symmetry wouldbe a timelike geodesic motion even though there exists an extra non-gravitational force in contrast with the case of thestabilized extra spatial dimension. In other words the presence of the extra non-gravitational three would not violate the Z2 symmetry.
We study the null bulk geodesic motion in the brane world in which the bulk metric has an un-stabilized extra spatial dimension. We find that the null bulk geodesic motion as observed on the 3-brane with Z<SUB>2</SUB> symmetry would be a timelike geodesic motion even though there exists an extra non-gravitational force in contrast with the case of the stabilized extra spatial dimension. In other words the presence of the extra non-gravitational force would not violate the Z<SUB>2</SUB> symmetry.
基金
The project supported by National Natural Science Foundation of China under Grant No.10175070
National Basic Research Project of China under Grant No.2003CB716300
