Small-world phenomena and the statistics of linear polymers

A regular lattice in which the sites can have long-range connections at a d istance l with a probability P(l) similar to 1(-delta), in addition to the short-range nearest neighbour connections, shows small-world behaviour for 0 less than or equal to delta less than or equal to delta (c). In the most appropriate physical example of such a system, namely, the linear polymer n etwork, the exponent delta is related to the exponents of the corresponding n-vector model in the n --> 0 limit, and its value is less than delta (c). Still, the polymer networks do not show small-world behaviour. Here, we sh ow that this is due to a (small value) constraint on the number, q, of long -range connections per monomer in the network. In the general delta -q spac e, we obtain a phase boundary separating regions with and without small-wor ld behaviour, and show that the polymer network falls marginally in the reg ular lattice region.