String theory as a universal language

TL;DR

Polyakov argues that string theory can serve as a universal language for gauge dynamics, exploring open strings in AdS spaces, D-brane dualities, and conformal gauge theories in higher dimensions. He shows that gluons can correspond to finite boundary modes of open strings in AdS-like backgrounds, analyzes the D-brane vs sigma-model viewpoints, and extends conformal theories to higher dimensions via AdS backgrounds with RR flux, proposing possible conformal fixed points in non-critical bosonic theories. He also offers speculative ideas on infrared screening of the cosmological constant, suggesting a link between vacuum energy, the Hubble scale, and AdS/CFT ideas. The work emphasizes how conformal invariance and boundary dynamics govern the gauge-string dictionary and highlights caveats and potential cosmological implications of these relations.

Abstract

This article, based on the Klein lecture, contains some new results and new speculations on various topics. They include discussion of open strings in the AdS space, unusual features of D-branes, conformal gauge theories in higher dimensions. We also comment on the infrared screening of the cosmological constant and on the "brane worlds"