Confinement deflection length
= Confinement deflection length
{title2=$\lambda\sim(R^2\ell_p)^{1/3}$}
A stiff chain's transverse wandering over contour <length> $s$ scales as $s^3/\ell_p$. Equating this to the squared confining radius gives the displayed deflection <length> when $R\ll\ell_p$. A free-energy cost of order $k_BT$ per deflection yields confinement <free energy> per inserted contour <length> of order $k_BT/\lambda$. Numerical prefactors depend on geometry and boundary constraints.