an introduction to statistical mechanics and thermodynamics second edition pdf
In preparing to write the preface to the second edition of this book, I realized anew my
debt to the work of Herbert B. Callen. He was not only my thesis advisor and my friend,
but it was through his teaching and his book on thermodynamics that I first understood
the subject in any depth. I take this opportunity once again to acknowledge how much
his pedagogy and advice have meant to my work.
The postulational approach to thermodynamics, which is primarily based on his work
and that of his thesis advisor, László Tisza, provides a clear basis for the theory. It is not
difficult to understand but can seem rather abstract when first encountered as a student –
as, indeed, it did to me many years ago. Many professors have told me that they thought
that Callen’s book was too daunting to give to their students, but that it was the book that
they consulted for thermodynamics.
Part I of my book originated as an introduction to Callen’s Thermodynamics in my
teaching. One difficulty that I had found as a student was that Callen’s book started
off presenting entropy and the postulates of thermodynamics in the first chapter, and
temperature as a partial derivative of the entropy in the second chapter. I had only a
vague idea at the time of what the entropy was, and its partial derivative with respect to
energy was a complete mystery. I have tried to avoid this difficulty in my own teaching of
thermodynamics by presenting the students with an explicit calculation of the entropy of
a classical ideal gas. All assumptions are stated, and all mathematics is explained. I felt –
and my students generally agreed – that they were then ready to understand Callen’s
Part II developed from my notes for teaching from Callen’s textbook. I found that
while the ideas in Callen’s postulates provided a great foundation for thermodynamics,
their specific form was less than ideal. For the first edition of this book, I separated them
into six new postulates, each of which expressed a separate idea. I also generalized the
postulates to include non-homogeneous systems.
I gave an explicit guide to the use of Jacobians in deriving thermodynamic identities,
which I have not found anywhere else, but which my students have found to be easy to
apply. Callen mentioned Jacobians in his first edition, but not in his second. Similarly,
I simplified the derivation of Maxwell relations, with the result that my students have
regarded them (correctly) as being easy to derive.
I also gave an explicit derivation of the stability criteria for second partial derivatives
with respect to intensive variables because many students had difficulty with them.
Parts III (classical statistical mechanics) and IV (quantum statistical mechanics) used
computer calculations extensively. They allowed many calculations to be carried out
explicitly. I firmly believe that the future of physics will rely heavily on the computer,
and I think that computation is currently being neglected in university curricula.