SUSCEPTIBILITY AND LOW-TEMPERATURE THERMODYNAMICS OF SPIN-1 2 HEISENBERG LADDERS/

The temperature dependence of the uniform susceptibility and the groun d-state energy of antiferromagnetic Heisenberg ladders with up to six legs has been calculated, using the: Monte Carlo loop algorithm. The s usceptibilities of even-leg ladders show spin gaps while those of odd- leg ladders remain finite in the zero-temperature limit. For small rat ios of intra- to interleg couplings, odd-leg ladders can be mapped at low temperatures to single chains. For equal couplings, the logarithmi c corrections at low temperatures increase markedly with the number of legs.