STATICS AND DYNAMICS OF CHARGE FLUCTUATIONS IN THE T-J MODEL

The equation for the charge vertex gamma of the t-J model is derived a nd solved in leading order of a 1/N expansion, working directly in ter ms of Hubbard operators. Various quantities which depend crucially on gamma are then calculated, such as the lifetime and the transport life time of electrons due to a charge coupling to other degrees of freedom and the charge-charge correlation function. Our results show that the static screening of charges and the dynamics of charge fluctuations d epend only weakly on J and are mainly determined by the constraint of having no double occupancies of sites.