%0 Journal Article %@ 1539-3755 %A Rios, Paolo %A Caldarelli, Guido %A Maritan, Amos %A Seno, Flavio %D 1996 %F eprints:1183 %I American Physical Society %J Physical Review E %K PACS: 05.40.+j, 02.50.-r %N 3 %P R2029-R2032 %T Optimal path and directed percolation %U http://eprints.imtlucca.it/1183/ %V 53 %X An efficient transfer matrix technique is introduced to study directed optimal paths in two and three dimensions. The roughness exponent ζ is 0.6325±0.0007 for the two-dimensional case and ζ=0.555±0.008 for the three-dimensional one, in agreement with the recent conjecture ζ=ν⊥/ν∥, where ν⊥ and ν∥ are the correlation length exponents of directed percolation. Exactly solvable examples are also analyzed.