David Lancaster | PubMed Health

PubMed2006

Statistical mechanics of multi-index matching problems with site disorder.

We study the statistical mechanics of multi-index matching problems where the quenched disorder is a geometric site disorder rather than a link disorder. A recently developed functional formalism is exploited that yields exact results in the finite-temperature thermodynamic limit. Particular attention is paid to the zero-temperature limit of maximal matching problems where the method allows us to obtain the average value of the optimal match and also sheds light on the algorithmic heuristics leading to that optimal match.

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PubMed2005

Statistical mechanics of combinatorial optimization problems with site disorder.

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.

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