RT Journal Article T1 Self-diffusion in simple models: Systems with long-range jumps A1 Asselah, A. A1 Lebowitz, J. L. A1 Brito López, Ricardo AB We review some exact results for the morion of a tagged particle in simple models. Then, we study the density dependence of the sill-diffusion coefficient D_(N)(ρ) in lattice systems with simple symmetric exclusion in which the particles can jump, with equal rates, to a set of N neighboring sites. We obtain positive upper and lower bounds on F_(N)(ρ) = N{(1 - ρ) - [D_(N)(ρ)/D_(N)(0)]}/[ρ(1 - ρ)] for ρ is an element of [0, 1]. Computer simulations for the square, triangular, and one-dimensional lattices suggest that FN becomes effectively independent of N for N greater than or equal to 20. PB Springer SN 0022-4715 YR 1997 FD 1997-06 LK https://hdl.handle.net/20.500.14352/58569 UL https://hdl.handle.net/20.500.14352/58569 LA eng NO © 1997 Plenum Publishing Corporation. We thank C. Landim, S. Olla, M. S. Ripoll, and H. T. Yau for useful discussions. This work was supported by NSF Grant 92-13424 4-20946. R.B. was also supported by D.G.I.C. y T. (Spain), project PB94-0265. NO NSF NO D.G.I.C. y T. (Spain) DS Docta Complutense RD 11 abr 2025