On compactification to six spacetime dimensions, the fundamental heterotic string admits as a a dual string whose effective worldsheet action couples… - Michael Duff

lies at the heart of quantum information theory, with applications to quantum computing, teleportation, cryptography and communication. In the apparently separate world of quantum gravity, the of radiating black holes has also occupied centre stage. Despite their apparent differences, it turns out that there is a correspondence between the two. ... Whenever two very different areas of theoretical physics are found to share the same mathematics, it frequently leads to new insights on both sides. Here we describe how knowledge of string theory and M-theory leads to new discoveries about Quantum Information Theory (QIT) and vice-versa (Duff 2007; Kallosh and Linde 2006; Levay 2006).

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.