### Thermodynamic Issues Related to Casimir Forces
from a Classical Physics Perspective

**Daniel C. Cole**

*Dept. of Manufacturing Engineering*

*15 St. Mary's Street*

*Boston University*

*Brookline, MA 02446 *

Using our present knowledge of Casimir forces, it is interesting
to return to early thermodynamic blackbody radiation analyses
and examine how they would be modified if these ideas were taken
into account. The first part of this talk dwells on the conventional
analysis entering into the Wien displacement law, as often still
reported in conventional textbooks in thermodynamics, statistical
mechanics, and quantum mechanics. A number of subtle, but critical,
assumptions are conventionally made that are clearly invalid when
one takes into account the presence of Casimir-type forces. If
these assumptions are not imposed, but the analysis is carried
out in more generality by properly accounting for the change in
the normal modes of the radiation as cavity changes are made,
then a generalized Wien displacement law can be derived that holds
with Casimir forces being present. In addition, however, a far
more surprising result is also obtained, namely, a derivation
falls out for the appropriate spectrum of classical electromagnetic
zero-point radiation, in order for this analysis to hold at temperature
*T*=0.

This talk then reviews related work where this similar analysis
has been applied to other systems, including *N* harmonic
electric dipole oscillators, and cavities of arbitrary shape that
are composed of perfectly conducting walls, all bathed in blackbody
radiation. There are both practical as well as purely theoretical
possible consequences of this work, as will be discussed here.