Physical Society Colloquium

Professor Stephen Shenker is the director of the Theory Institute within the physics department at Stanford University. Professor Shenker is a distinguished theoretical physicist whose research focuses on string theory and M-theory, which are the state-of-the-art in understanding the laws of nature at the smallest possible distance scales.

Quantum Mechanics and General Relativity, the modern theory of Gravity, are two of the great intellectual achievements of physics during the Twentieth Century. But for most of that century these two great theories existed in isolation from one another, despite the best efforts of generations of theoretical physicists to unify them. In this lecture I will describe some of the formidable obstacles to this unification, and the recent progress that for the first time has given us a candidate for a consistent theory of quantum gravity.

String Theory is the best candidate known for a unified theory of all basic interactions. In this lecture I will describe our current understanding of this theory. I will describe the recent remarkable progress that has convinced us that String Theory describes a consistent theory of quantum gravity, and will discuss some of the many mysteries remaining to be answered. I will briefly mention experiments that may help us understand the theory better.