I am a researcher working in the mathematical physics group at the Mathematical Institute. I am working on dualities of string and field theories, as well as compactifications of string theory. This involves a whole lot of fascinating mathematics, in particular (algebraic) geometry.
Recently, I have worked a lot on manifolds of 'exceptional holonomy' which only exist in dimension 7 (holonomy $G_2$) and 8 (holonomy $Spin(7)$). These are fairly special and intriguing geometries, the existence of which is tightly linked to exciting physics: compactifications of MTheory (or 11dimensional supergravity) on such spaces gives theories in four and three dimensions with minimal supersymmetry. It is hence very interesting to understand constructions and properties of such spaces, which is, however, a hard problem in mathematics. By probing such spaces with various string theories and exploiting dualities between different string compactifications, we have nevertheless been able to make substantial progress in the last two years (and there is plently left to do, so you are welcome to join).
Here are a some recent talks of mine on the subject.
 https://www.youtube.com/watch?v=SVNUDpCeB0 (video taken at the 2018 FTheory meeting in Madrid, aimed at an audience familiar with FTheory)

https://sites.duke.edu/scshgap/andreasbraunlectures/ (videos of two talks at meetings of the Simons Collaboration on Special Holonomy in Geometry, Analysis, and Physics, aimed at a maths audience)

http://people.maths.ox.ac.uk/braun/talks/g2.pdf (slides of an overview talk aimed at a general string theory audience)
If you would like to see me declare my love for K3 surfaces, you can do so by watching this talk I gave at the Field's Institute on the duality between heterotic and IIA string theory: http://www.fields.utoronto.ca/talks/titletba285
I wrote an entry for the Oxford Mathematics Alphabet about CalabiYau manifolds, https://www.maths.ox.ac.uk/aboutus/lifeoxfordmathematics/oxfordmathe...
My upbringing as a student has been as a theoretical particle physicist. As things go, I first got involved with string theory and then with the mathematics needed to make progress.
I have worked a lot on Ftheory, which is a very elegant geometrization of the $SL(2,Z)$ selfduality of type IIB string theory. This works by replacing the complexified string coupling of type IIB string theory by a elliptic curve (i.e. a torus), and nicely ties together MTheory, type IIB string theory and heterotic E8 x E8 string theory. A basic introduction can be found here: http://people.sissa.it/~cecotti/FNOTES10.pdf
Although this is great fun in its own right and has led to many insights, FTheory provides an interesting starting point for 'string phenomenology'. This concerns the question how we should think about string theory in relation to the known low energy physics as described by the Standard Models of particle physics and cosmology. A review of why Ftheory is interesting for string phenomenology can be found here: http://arxiv.org/abs/1009.3497.
String Theory is a very beautiful theory which seems to be unique as a 10 dimensional theory, but it is presently unclear how we should think about it in relation to our fourdimensional world. An obvious way to reconcile 10 with 4 is to consider solutions of string theory which effectively look fourdimensional below a certain energy scale. One of the fundamental problems of String Theory is that there are a huge number of possibilities to do this. Although opinions on what this means differ wildly, it is fair to say that many things about this 'landscape' are poorly understood. Here are a few questions:
 Can we find a solution of String Theory which perfectly reproduces observed physics ?
 Is the set of effectively fourdimensional solutions finite or does it become finite once we impose additional restrictions ?
 Is every consistent fourdimensional theory an effective description of some string theory compactification ?
 Is (a welldefined subset of) every consistent fourdimensional theory an effective description of some string theory compactification ?
 Do the solutions of String Theory have universal features (maybe upon demanding additional restrictions) ?
 Are there correlations between (desirable) features ?
 What has cosmological evolution to say about all this ?
Attacking such questions requires a fair deal of interesting mathematics to be developed.
+44 1865 615181
Address
University of Oxford
Andrew Wiles Building
Radcliffe Observatory Quarter
Woodstock Road
Oxford
OX2 6GG
Recent Publications:
NS5branes and line bundles in heterotic/Ftheory duality
PHYSICAL REVIEW D
issue 12
volume 98
page 126004
(12 December 2018)
Full text available
Infinitely many M2instanton corrections to Mtheory on G(2)manifolds
JOURNAL OF HIGH ENERGY PHYSICS
issue 9
volume 2018
(13 September 2018)
Full text available
Spin(7)manifolds as generalized connected sums and 3d N=1 theories
JOURNAL OF HIGH ENERGY PHYSICS
issue 6
(20 June 2018)
Full text available
Spin(7)manifolds as generalized connected sums and 3d N = 1 $$ \mathcal{N}=1 $$ theories
Journal of High Energy Physics
issue 6
volume 2018
(20 June 2018)
Discrete Symmetries of CalabiYau Hypersurfaces in Toric FourFolds
COMMUNICATIONS IN MATHEMATICAL PHYSICS
issue 3
volume 360
page 935984
(June 2018)
Full text available
Research interests:
 compactifications of String/Mtheory and the resulting effective field theories
 CalabiYau manifolds (in complex dimensions 1 to 4)
 $G_2$ manifolds, Spin(7) manifolds
 geometry and string dualities
 singularities and the associated physics
 mirror symmetry
Further details:
I like music a lot and often listen to resonance.fm while working. If I had to pick one, my favourite movie would be 'Down by Law' by Jim Jarmusch, but it is hard to choose. I am a Linux fanboy of sorts. My favourite colour is blue. In the late summer, I like to hunt for wild mushrooms, but won't tell you where to find them (secret of the trade). I like cacti and coriander. We live in a pretty, big, and interesting universe.
Teaching:
Here are some lectures I have recently given on how to use the opensource mathematics software sage (http://www.sagemath.org/) to do computations with CalabiYau manifolds: http://www.mth.kcl.ac.uk/~ss299/GGI/scheduleSchool.html
Major / recent publications:
you can find a complete list of my publications here:
https://inspirehep.net/search?ln=en&ln=en&p=author%3AA.Braun.1