  Zero modes of modular Hamiltonian of one interval are found in momentum space
for two dimensional massless free scalar theory. Finite correlators are
extracted from separate region connected correlation functions with the
insertion of zero modes. Correlators of $(n,1)$-type are claimed to be
conformal block up to a set of theory dependent constants. We fix the
correlators of $(2,1)$-type with the coefficients of three point function in 2d
CFTs.
