FM 2000-8 mp_arc@math.utexas.edu \# 00-89 math-ph@xxx.lanl.gov \# 0002052 Authors: Federico Bonetto, Joel L. Lebowitz and Luc Rey-Bellet Title: Fourier's Law: a Challenge to Theorists Abstract: We present a selective overview of the current state of our knowledge (more precisely of our ignorance) regarding the derivation of Fourier's Law, J(r) = -k \nabla T(r); J the heat flux, T the temperature and k, the heat conductivity. This law is empirically well tested for both fluids and crystals, when the temperature varies slowly on the microscopic scale, with k an intrinsic property which depends only on the system's equilibrium parameters, such as the local temperature and density. There is however at present no rigorous mathematical derivation of Fourier's law and ipso facto of Kubo's formula for k, involving integrals over equilibrium time correlations, for any system (or model) with a deterministic, e.g. Hamiltonian, microscopic evolution. Keywords: Fourier's law, heat conduction, steady state, Green-Kubo formula Addresses: F.B.: IHES, 75 route de Chartres, 91440 Bures sur Yvette, France J.L.L.: Department of Mathematics and Physics, Rutgers University, 110 Frelinghuysen Road, Piscataway NJ 08854. L.R.-B.: Department of Mathematics, University of Virginia, Kerchof Hall, Charlottesville VA 22903 e-mail: bonetto@ihes.fr lebowitz@math.rutgers.edu lr7q@virginia.edu