Heat conduction phenomena are studied theoretically using computer simulati
on. The systems are crystal with nonlinear interaction: and fluid of hard-c
ore particles. Quasi-one-dimensional systems of the size L-x x L-y x L-z(L-
z much greater than L-x, L-y) are simulated. Heat baths are put in both end
s: one has a higher temperature than the other. In the case of the crystal,
the interaction potential V has a fourth-order nonlinear term in addition
to the harmonic term, and the Nose-Hoover method is used for the heat baths
. In the case of the fluid, the stochastic boundary condition is charged, w
hich performs the function of the heat baths. Fourier-type heat conduction
is reproduced in both crystal and fluid models in a three-dimensional syste
m, but it is not observed in lower-dimensional systems. The autocorrelation
function of heat flux is also observed and long-time tails of the form sim
ilar to t(-d/2), where d denotes the dimensionality of the system, are conf
irmed.