The Surprising Simplicity of Scattering Amplitudes

Abstract:

Quantum field theory is the modern manifestation of "force equals mass times acceleration": it is the underlying, mathematical framework in which understand and describe physical laws today—from the most fundamental to the merely effective or approximate. Quantum field theory is the modern manifestation of "force equals mass times acceleration": it is the underlying, mathematical framework in which understand and describe physical laws today—from the most fundamental to the merely effective or approximate. Quantum field theory is the modern manifestation of "force equals mass times acceleration": it is the underlying, mathematical framework in which understand and describe physical laws today—from the most fundamental to the merely effective or approximate.

While the foundations of the subject have been in place for more than a half-century, the way we understand, teach, and use quantum field theory is rapidly evolving—fueled by a desire to explain an embarrassing discrepancy between the difficulty of making predictions for experiment and the near-universal, mocking simplicity of the predictions we ultimately make.

In this talk, I illustrate the ubiquity and depth of such simplicity, and describe some of the recent progress that has been made to make it less surprising (to the theorists doing the calculations, at least). Much of these developments have been made in the context of especially simple quantum field theories, but the lessons learned often have much wider applications. I outline several of these recent developments, and discuss the concrete roads ahead.