I am mainly interested in understanding the workings of the quantum field theories which underlie the phenomena of particle physics. In recent years this has lead me to study issues in string theory (the construction of conformal field theories corresponding to solitons of various kinds) and in quantum gravity (the problem of Hawking radiation and the endpoint of black hole evaporation).

I have an avocational interest in the application of field theory techniques to condensed matter problems that has led to work in dissipative quantum mechanics and the quantum mechanics of the fracture of materials.

• C. Callan, S. Giddings, J. Harvey and A. Strominge, "Evanescent Black Holes,"
• Phys. Rev. D45, R1005 (1992).
• C. Callan and F. Wilczek, "On Geometric Entropy", Phys. Lett. B333, 55 (1994).
• C. Callan, I. Klebanov, A. Ludwig and J. Maldacena, "Exact Solution of a Boundary Conformal Field Theory", Nuc. Phys. B422, 417 (1994).
• C. Callan, "It's A Snap: Instantons and the Rupture of Polymers", in "Topics in Quantum Field Theory: Modern Methods in Fundamental Physics" D.H.Tchrakian ed., World Scientific Publishers 1995.
• C. Callan and J. Maldacena, "D-Brane Approach to Black Hole Quantum Mechanics",  hep-th/9602043 and Nuc. Phys. B472, 591 (1996).