ABSTRACT
We proceed to devise a model to study the effect of
slow heat conduction. The physical basis for this model is
explained as follows.
Again imagine a block spin σ(χ ) which is the net
spin density in the block located at x . The “r e s e rv o ir "
in direct contact with σ (χ ) consists of a ll motions within
the block, including lattice vibrations, spin fluctuations
of wavelengths shorter than the block size, electronic
motions, etc. We have approximated the net effect of the
rese rvo ir by a noise in the preceding models. The noise
has been assumed to be rapid ly varying and has zero c o r -
relation time. Now i f the conduction of heat is slow,
there w il l be slow accumulation and depletion of energy
and thereby the effect can no longer be included as a part
of the noise of short corre la tion time and must be singled
out.
