title: Entropic tightening of vibrated chains.
abstract: We investigate experimentally the distribution of configurations of a ring with an elementary topological constraint, a "figure-8" twist. Using a system far from thermal equilibrium, a vibrated granular chain, we show that configurations where one loop is small and the second is large are strongly preferred. Despite the highly non-equilibrium nature of the system, our results are consistent with recent predictions for equilibrium properties of topologically-constrained polymers. The dynamics of the tightening process weakly violates a (coarse-grained) detailed balance, indicating that the unexpected correspondence with an equilibrium entropic approach is not exact.
authors.affiliation: Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: M B
authors.initials: MB
authors.lastname: Hastings
authors.forename: Z A
authors.initials: ZA
authors.lastname: Daya
authors.forename: E
authors.initials: E
authors.lastname: Ben-Naim
authors.forename: R E
authors.initials: RE
authors.lastname: Ecke