QUASI-ONE-DIMENSIONAL SPIN-1 2 HEISENBERG MAGNETS IN THEIR ORDERED PHASE - CORRELATION-FUNCTIONS/

We study weakly coupled antiferromagnetic spin chains in their ordered phase by combining an exact solution of the single-chain problem with a random-phase-approximation analysis of the interchain interaction. A single chain is described by a quantum Sine-Gordon model and dynamic al staggered susceptibilities are determined by employing the form-fac tor approach to quantum correlation functions. We consider both antife rromagnetic order encountered in quasi-one-dimensional materials such as KCuF3 and spin-Peierls order as found in CuGeO3. [S0163-1829(97)009 41-7].