Infrared screening of the cosmological constant
Alexander M. Polyakov is a theoretical physicist, formerly at the Landau Institute in Moscow, currently at Princeton University.
He is known for a number of basic contributions to quantum field theory, including work on what is now called the 't Hooft-Polyakov monopole in non-abelian gauge theory. His paper from 1984 on infinite conformal symmetries in two-dimensional quantum field theory, with Alexander Belavin and Alexander Zamolodchikov, has classic status. His path integral formulation of string theory had profound and lasting impacts on the conceptual and mathematical understanding of the theory. He also played an important role in elucidating the conceptual framework behind renormalization. He formulated pioneering ideas in gauge/string duality long before the breakthrough of AdS/CFT using D-branes. Other insightful conjectures that came years or even decades before active work by others include integrability of gauge and string theories and certain ideas about turbulence.
Alexander Polyakov was awarded the Dirac Medal and the Dannie Heineman Prize for Mathematical Physics in 1986, the Lorentz Medal in 1994, and the Oskar Klein Medal in 1996.
He has been elected to the Russian Academy of Sciences in 1984 and the U.S. National Academy of Sciences in 2005.