My research interest lies in the representation theory of Lie groups, particularly branching laws of representations. The branching law describes how a given representation decomposes when restricted to a subgroup, which is a mathematical formulation of the breaking symmetry. In my thesis, I studied the branching laws of a certain class of representations of real reductive groups (the so-called derived functor modules) in terms of a geometric realization of representations by using D-modules on the flag variety.