Consider a linear chain of molecules. The polarization p of each molecule is described by the classical equation of motion,
where E is the local electric field. The polarization is aligned along the
chain, and each molecule is exposed to the electric field generated by the
others. The p=0 ground state of this system becomes unstable if the
polarizability exceeds
.
The susceptibility characterizes the response to an external perturbation.
The relevant perturbation for this system is an external
electric field wave, 
.
The response is a polarization wave, 
.
The susceptibility is defined as 
.
(a) Calculate the susceptibility as a function
of the wavenumber k at 
for 
.
Show that 
diverges at
as 
,
and calculate the exponent of the divergence, 
.
(b) Calculate 
at 
,
Laszlo Mihaly
Thu Oct 31 13:23:11 EST 1996
Cover Page
.
