# 2011 Rayleigh Medal and Prize

Professor Arkady Tseytlin

*Imperial College London*

*For his contributions to the understanding of string theory and of its relation to conventional quantum field theories, and in particular to non-abelian gauge theories that form the basis for our current theoretical description of elementary particle interactions.*

Arkady Tseytlin is one of the world’s leading figures in the development of string theory and pioneered the decipherment of its relations to the key structures of fundamental physics. His work has provided a firm foundation both for the understanding of gravitational dynamics from string theory and also for the profound relation to the nonabelian gauge theories which are the basis of our understanding of all the non-gravitational fundamental forces.

His pioneering work on the sigma model approach laid the foundation for a vast edifice of work on gravitational effective field theories, providing one of the key points of contact between string theory and applications to known physics. His discovery that the leading part of the tree-level open string theory effective action is the same as the “non-linear electrodynamics” action, proposed by Born and Infeld in 1933, has had numerous applications in the studies of D-branes and is in particular the basis of many current applications of branes in cosmology.

He has made fundamental contributions to the study of extended p-brane solutions (generalised membranes) in supergravity, which is the field-theory limit of superstring theory. In particular, he found a class of supergravity solutions describing black-hole string states with finite entropy and with unbroken supersymmetry. He also suggested a general method for constructing the class of intersecting p-brane solutions; taken together, this has led to the establishment of a microscopic origin of black-hole entropy in string theory, which is a historic achievement of string theory.

In recent work of the greatest importance, he has laid out in detail the working of duality between non-abelian gauge theories and strings in the near-horizon region of a stack of many D-branes, where spacetime asymptotically approaches the product of an anti-de Sitter space and a sphere. He has shown how to quantise strings in such backgrounds and has pioneered the application of integrable quantum field theory methods to this problem. He developed a semiclassical approach to computation of the spectrum of anomalous dimensions in the dual maximally supersymmetric Yang-Mills theory and suggested a string theory explanation for the remarkable dual conformal symmetry of gluon scattering amplitudes.