GUIDED REPLICATION OF RANDOM CHAINS - A NEW MONTE-CARLO METHOD

The authors introduce a new Monte Carlo method to study random chains. The method uses (i) a link by link growth procedure of the chain, (ii) a chain replication procedure based on Boltzmann weights. They apply it to various cases in two and three dimensions (pure self-avoiding walk, repulsion between nearest-neighbour links and attraction between the chain extremities, etc.). When the competition (or frustration) between the different interaction terms increases, the chain may get trapped in local minima: to overcome this problem, they introduce a guiding field (or potential) ( phi i(r)). Step (ii) is now performed in the presence of this guiding field, which makes the chain population temporarily non-Boltzmannian. However, when the chain is completed, the final population obeys again the Boltzmann law. They study simple cases, where ( phi i(r)) may be chosen on physical grounds.