E. Roger Cowley Home Page

E. Roger Cowley


Research Interests

I am interested in the theory of the thermal properties of crystals and particularly the phonon contributions to them. I use either traditional lattice dynamics techniques or computer simulations. Over the last few years much of my work, in collaboration with George Horton, has been on the development of the Effective Potential method as a means of including quantum effects in Monte Carlo simulations. I have also recently revived an old interest in ferroelectric materials, from my days with Bill Cochran, and have developed a model of tin telluride which shows a soft mode phase transition. I also have a long-term interest, shared with Ramesh Shukla, in the calculation both of thermal properties and scattering properties using anharmonic perturbation theory.

The squared frequency of the soft mode in the model of tin telluride. The frequency of the mode goes to zero as the transition temperature is approached, either from above or below. (Physica A, 232, 585-599 (1996))

I have recently spent some time constructing an optical replica of the type of telescope used by Galileo. My ideas on the field of view are described here.

If you feel that classical mechanics holds no surprises for you, take a look at the two papers in The Physics Teacher that I published recently with George Horton and Brian Holton! (The Physics Teacher, vol 36, pp 24-26, and vol 37, pp 188-191)

Short curriculum vitae

I get two retirement gifts:

Course web pages:

Elements of Physics I
Elements of Physics II
Electric Circuits I
Electric Circuits II
Modern Physics
Thermal Physics I
Physics Computer Lab
Physical Chemistry II

Recent Papers

Anomalous behavior of higher-harmonic spin density waves in Mn3Si.
S. Tomiyoshi, E. R. Cowley, and H. Onoder, Phys. Rev. B 73, 024416 (2006).

Selected topics in lattice dynamics: a critical review (including breathers).
G.K. Horton and E.R. Cowley, Chaos, 13, 667 (2003).

Inclusion of higher order anharmonic contributions in self-consistent phonon theory.
R.C. Shukla and E.R. Cowley, Phys. Rev. B, 62, 3232 (2000).

Thermal and elastic properties of solid neon.
D. Acocella, G.K. Horton, and E.R. Cowley, Phys. Rev. B, 61, 8753 (2000).

Successful theory of anharmonicity in the classical limit.
E.R Cowley and R.C. Shukla, Phys. Rev. B, 60, 14500-14502 (1999).

Another surprise in mechanics.
E.R. Cowley, G.K. Horton, and B.E. Holton, The Physics Teacher, 37, 188-191 (1999).

Summation of free-energy diagrams of an anharmonic crystal and equation of state for a Lennard-Jones solid.
R.C. Shukla and E.R. Cowley, Phys. Rev. B, 58, 2596-2602 (1998).

A thought provoking demonstration.
E.R. Cowley, B. Holton, and G.K. Horton, The Physics Teacher, 36, 24-26 (1998).

Generalized sum rules for the moments of a one-phonon spectral function.
J. Phys.: Condens. Matter, 9, 1719-1727 (1997).

Studies of the Phase Transition in a Model of Tin Telluride.
Ferroelectrics, 194, 227-238 (1997).

Self-consistent phonon studies of a model diatomic ferroelectric.
Physica A, 232, 585-599 (1996).

Validity of the low coupling approximation in the effective-potential method.
D. Acocella, G.K. Horton, and E.R. Cowley, Phys. Lett. A, 212, 161-166 (1996).

Physics department home page

Last revised 5/2/2009