Citation | The most significant of Cardy's wide-ranging contributions to theoretical physics concern the high energy behavior [sic] of scattering amplitudes of elementary particles and critical phenomena in statistical mechanics. A common theme has been quantum field theory. In 1984 Soviet field theorists demonstrated that the property of conformal covariance imposes severe restrictions on behavior of two-dimensional systems. Cardy has taken this principle and turned it into a precise quantitative tool for examining two-dimensional criticality. It provides a broadly unifying and mathematically elegant theory, predicting and superceding [sic] the older, less powerful concepts of scaling and universality.
He has used conformal maps to relate bulk properties to those of a system of finite size. Since the latter can be obtained accurately by the transfer matrix method, this provides a direct, practical and quantitative way of studying the critical behavior of many models. Cardy also realized and exploited the invariance of the partition function with respect to modular transformations as a further tool in classifying possible critical behavior. In a sense Cardy has "solved" two-dimensional critical statistical mechanics. His ideas have also been influential on the string theory of elementary particles. |