# Michael Duff (physicist)

Michael James Duff FRS (born 28 January 1949) is A British theoretical physicist. In 2017 he was awarded the Dirac Medal of the IOP.

## Quotes

* In 1973 two Salam protégés (Derek Capper and the author) discovered that the conformal invariance under Weyl rescalings of the metric tensor g$_{μν}$(x → Ω$^2$(x) g$_{μν}$(x) displayed by classical massless field systems in interaction with gravity no longer survives in the quantum theory. Since then these Weyl anomalies have found a variety of applications in black hole physics, cosmology, string theory and statistical mechanics.
** (1994). "Twenty years of the Weyl anomaly". Classical and Quantum Gravity 11 (6): 1387–1403. DOI:10.1088/0264-9381/11/6/004.
* On compactification to six spacetime dimensions, the fundamental heterotic string admits as a soliton a dual string whose effective worldsheet action couples to the background fields of the dual formulation of six-dimensional supergravity.
** (1995). "Strong/Weak coupling duality from the dual string". Nuclear Physics B 442 (1–2): 47–63. DOI:10.1016/S0550-3213(95)00070-4.
* Superunification underwent a major paradigm shift in 1984 when eleven-dimensional supergravity was knocked off its pedestal by ten-dimensional superstrings. This last year has witnessed a new shift of equal proportions: perturbative ten-dimensional superstrings have in their turn been superseded by a new non-perturbative theory called M-theory, which describes supermembranes and superfivebranes, which subsumes all five consistent string theories and whose low energy limit is, ironically, eleven-dimensional supergravity.
** (1996). "M Theory (The Theory Formerly Known as Strings)". International Journal of Modern Physics A 11 (32): 5623–5641. DOI:10.1142/S0217751X96002583.
* 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 elementary particles. 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.
** (2001). "The world in eleven dimensions: A tribute to Oskar Klein". (quote on pp. 2–3)
* Quantum entanglement 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 Hawking effect 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).
** Sánchez Sorondo, Marcelo; Zichichi, Antonino. eds. "Black Holes and QuBits by Michael J. Duff". Subnuclear Physics: Past, Present and Future; Proceedings of the International Symposium, held 30 October - 2 November 2011, held in Vatican City. Scripta Varia, volume 119. Pontifical Academy of Sciences. 2014. pp. 488–496. (quote on p. 488)

## External links

Encyclopedic article on Michael Duff (physicist) on Wikipedia