Superunification underwent a major paradigm shift in 1984 when eleven-dimensional supergravity was knocked off its pedestal by ten-dimensional supers… - Michael Duff

In 1973 two protégés (Derek Capper and the author) discovered that the conformal invariance under Weyl rescalings of the metric tensor g_μν(x → Ω²(x) g_μν(x) displayed by classical massless field systems in interaction with gravity no longer survives in the quantum theory. Since then these have found a variety of applications in black hole physics, cosmology, string theory and statistical mechanics.

Theoretical physicists like to ask the big questions: How did the Universe begin? What are its fundamental constituents? What are the laws of nature that govern these constituents?
The smallest constituents of matter are, by definition, the s. But what is an elementary particle, exactly? How do we know when we have reached the bottom line? Well, it turns out to be easier to say what an elementary particle is not.

On compactification to six spacetime dimensions, the fundamental heterotic string admits as a a dual string whose effective worldsheet action couples to the background fields of the dual formulation of six-dimensional supergravity.