The polarization of a molecule is described by the anharmonic equation of motion,
A linear chain of lattice spacing a is made of these molecules. The polarization is parallel to the chain, and each molecule is exposed to the electric field of the others. The temperature is zero, and quantum effects are negligible.
(a) For fixed values of the other parameters and
the system develops a spontaneous polarization.
What is the critical value of 
?
(b) Calculate the magnitude of the static polarization 
as a
function of . Show that, close to 
,
, and calculate the
exponent 
.
Laszlo Mihaly
Thu Oct 31 13:23:11 EST 1996
Cover Page
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