1211.1110 (Wei-Jie Fu)

Hierarchy Structure of the Bethe-Salpeter Equations    [PDF]

Wei-Jie Fu

Hierarchy structure of the Bethe-Salpeter (BS) equations is found. We also employ this structure to greatly improve on the approximations for the BS kernel. Resummation of the BS kernel in $t$ and $u$ channels to infinite order is equivalent to truncate the effective action to infinite order. Our approximation approaches insure that the theory can be renormalized, which is very important for numerical calculations. Two-point function can also obtained from the four-point one through flow evolution equations resulting from the exact renormalization group. BS equations of different hierarchies and the flow evolution equation for the propagator constitute a closed system, which can be solved completely.

View original: http://arxiv.org/abs/1211.1110