Charge-spin separation in the t-J model: An effective-field-theory approach

A low-energy effective field theory of the t-J model for the normal state and the antiferromagnetic state is derived in the slave-fermion representation assuming a short-range antiferromagnetic order. It takes a form of the nonlinear CP1 sigma model of spins coupled with the nonrelativistic fermion fermion for doped holes in a U(1) gauge-invariant manner. The renormalization-group equations on the one-loop level are calculated a la Polyakovʹs prescription. It is discussed how the possible charge-spin separation phenomenon of cuprate high-Tc superconductors may be described in terms of the renormalization group of the effective field theory.