title: Statistical mechanics of combinatorial optimization problems with site disorder.
abstract: We study the statistical mechanics of a class of problems whose phase space is the set of permutations of an ensemble of quenched random positions. Specific examples analyzed are the finite-temperature traveling salesman problem on several different domains and various problems in one dimension such as the so-called descent problem. We first motivate our method by analyzing these problems using the annealed approximation. Then in the limit of a large number of points we develop a formalism to carry out the quenched calculation. This formalism does not require the replica method, and its predictions are found to agree with Monte Carlo simulations. In addition our method reproduces an exact mathematical result for the maximum traveling salesman problem in two dimensions and suggests its generalization to higher dimensions. The general approach may provide an alternative method to study certain systems with quenched disorder.
authors.affiliation: Laboratoire de Physique Théorique, UMR CNRS 5152, IRSAMC, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse Cedex 04, France.
authors.forename: David S
authors.initials: DS
authors.lastname: Dean
authors.forename: David
authors.initials: D
authors.lastname: Lancaster
authors.forename: Satya N
authors.initials: SN
authors.lastname: Majumdar