Michael Duff

Michael Duff is professor of theoretical physics at Imperial College London. \;\;

He made foundational contributions to string theory and M-theory. \;\;


Among Duff’s former students is Hisham Sati.



On the open problem of formulating M-theory:

Duff 96, totality of Section 6:

The overriding problem in superunification in the coming years will be to take the Mystery out of M-theory, while keeping the Magic and the Membranes.

Duff 98a, last paragraph (p. 6):

Despite all these successes, physicists are glimpsing only small corners of M-theory; the big picture is still lacking.


Indeed future historians may judge the late 20th century as a time when theorists were like children playing on the seashore, diverting themselves with the smoother pebbles or prettier shells of superstrings while the great ocean of M-theory lay undiscovered before them.

Duff 98b, p. 6:

we are only just beginning to scratch the surface of the ultimate meaning of M-theory, and for the time being therefore, M stands for Magic and Mystery too.

Duff 99, p.330:

future historians may judge the period 1984-95 as a time when theorists were like boys playing by the sea shore, and diverting themselves with the smoother pebbles or prettier shells of perturbative ten-dimensiorial superstrings while the great ocean of non-perturbative eleven-dimensional M-theory lay all undiscovered before them.

Interview with Mike Duff by Graham Fermelo, The universe speaks in numbers – Interview 14 (web):

(17:04) The problem we face is that we have a patchwork understanding of M-theory, like a quilt. We understand this corner and that corner, but what’s lacking is the overarching big picture. So directly or indirectly, my research hopes to explain what M-theory really is. We don’t know what it is.

In a certain sense, and this is not a popular statement, I think it’s premature to be asking: “What are the empirical consequences”, because it’s not yet in a mature enough state, where we can sensibly make falsifiable prediction.

Duff interview at M-Theory-Mathematics 2020:

(06:59) But the matrix model itself was not all of M-theory; it was a corner of M-theory, and it told us certain interesting things, but there were interesting things about M-theory that it didn’t tell us.

(07:13) I think we are still looking, in fact, for what M-theory really is.

(07:19) We have a patchwork picture. We understand various corners. But the overarching big picture of M-theory is still waiting to be discovered, in my view.

(08:12) M-theory in 1995 was very promising, and it’s taught us a lot about the fundamental interactions; but the final theory is still not with us.

(12:46) I wouldn’t like to predict what the ultimate picture of M-theory will be; I imagine it will be something quite different from what we can imagine now.

(16:36) That’s why I think M-theory is not yet in a mature enough stage for us to make falsifiable predictions.

(16:44) We don’t understand the theory sufficiently well yet to do so.

Selected writing

On double dimensional reduction of the super-membrane (the M2-brane) to the Green-Schwarz superstring:

On quantization of the M2-brane Green-Schwarz sigma-model:

On Kaluza-Klein compactification

  • Michael Duff, Kaluza-Klein Theory in Perspective, Proc. of the Symposium: The Oskar Klein Centenary, World Scientific, Singapore. 1994. (arXiv:hep-th/9410046)

and specifically in supergravity:

On black M2-brane-solutions to D=11 supergravity:

On M-theory:

On the brane scan which classifies super pp-brane sigma-models given by Green-Schwarz action functionals:

  • Michael Duff, Supermembranes: the first fifteen weeks CERN-TH.4797/87 (1987) (scan)

On string-string duality:

and specifically on the I8-term:

category: people

Last revised on May 16, 2020 at 04:34:07. See the history of this page for a list of all contributions to it.