Effect of Nambu-Goldstone modes on wave-number- and frequency-dependent longitudinal correlation functions

We discuss the effect of Nambu-Goldstone modes on the longitudinal wave-number- and frequency-dependent order-parameter correlation functions in the ordered phase. We find that the static wave-number-dependent correlation function diverges as q^-ε (ε=4-d) for small q and the linear response function for a time-dependent Ginzburg-Landau model, with $q=0$, diverges as ω^-ε2 for small frequencies. The consequences of these effects are discussed.