  The scaling of the bond-bond correlation function $C(s)$ along linear polymer
chains is investigated with respect to the curvilinear distance, $s$, along the
flexible chain and the monomer density, $\rho$, via Monte Carlo and molecular
dynamics simulations. % Surprisingly, the correlations in dense three
dimensional solutions are found to decay with a power law $C(s) \sim
s^{-\omega}$ with $\omega=3/2$ and the exponential behavior commonly assumed is
clearly ruled out for long chains. % In semidilute solutions, the density
dependent scaling of $C(s) \approx g^{-\omega_0} (s/g)^{-\omega}$ with
$\omega_0=2-2\nu=0.824$ ($\nu=0.588$ being Flory's exponent) is set by the
number of monomers $g(\rho)$ contained in an excluded volume blob of size
$\xi$. % Our computational findings compare well with simple scaling arguments
and perturbation calculation. The power-law behavior is due to
self-interactions of chains on distances $s \gg g$ caused by the connectivity
of chains and the incompressibility of the melt. %
