Thermal fluctuation in low dimensional systems - an experimental, computational and analytical study*

We apply a near optimal density matrix renormalization group scheme (T-DMRG) to weakly coupled spin-half ladders. By doing so, one can reach sufficiently good resolution in the calculation of spin-spin correlations at finite temperature. We compare the results with analytic predictions such as the one of the Tomonaga Luttinger liquid, and experiments on compounds such as (C$_5$H$_{12}$)$_2$ Cu Br$_2$ Cl$_2$.