The phenomena of capillarity and (partial) wetting have been studied for two centuries, yet they continue to be of great current interest. After a brief historical review, I will discuss some recent results on the associated minimal-surface problem. In conclusion, I will draw some analogies with problems facing present-day string theory.

Boundary string field theory is an open string field theory which has been originally formulated on a flat target space. In this talk I present recent progress in the study of BSFT in curved space backgrounds. Starting from a factorization property of the associated path-integral, non-local open string couplings can be identified which implement shifts in the closed string background. This generally affects the stability of D-branes, which is analyzed with renormalisation group methods. Evidence for the conjectured flow towards D-branes in curved space is presented for the example of a SU(2) WZW model.

I shall discuss various solitons which are possible in a ferromagnetic medium. Examples include domain walls, magnetic bubbles, vortex rings and Hopf solitons.

(check the triangle webpage under menu 'triangle' for directions to the seminar room)

Ten-dimensional IIB supergravity is invariant under the symmetry group SL(2.R). We give a classification of all the forms that are present in the IIB supersymmetry algebra as representations of SL(2,R), and we show under which conditions these forms are associated to branes whose effective actions are kappa symmetric. We use these results to give a simple universal SL(2,R)-invariant expression for all IIB brane actions.

I will discuss an instanton solution preserving AdS boundary conditions. It arises in a compactification of M-theory to four dimensions, keeping a single scalar coupled to gravity with a phi to the 4th potential. We study the holography of this solution in the context of a toy model, where the effective boundary CFT is a conformally coupled scalar with a phi to the 6th potential in three dimensions. We match bulk and boundary instanton solutions as well as fluctuations around them. Using a form of radial quantization we show that quantum states in the bulk correspond to multiply-occupied single particle states in the boundary theory. I will discuss the interpretation of the instanton in the dual CFT as a deformation by a triple-trace operator, and how the instanton signals an instability of the theory under this deformation.

We develop a systematic and efficient method of counting single-trace and multi-trace BPS operators with two supercharges, for world-volume gauge theories of N D-brane probes for both large and finite N. The techniques are applicable to generic singularities, orbifold, toric, non-toric, complete intersections, et cetera, even to geometries whose precise field theory duals are not yet known. The so-called Plethystic Exponential provides a simple bridge between the defining equation of the Calabi-Yau, the generating function of single-trace BPS operators and the generating function of multi-trace operators. Mathematically, fascinating and intricate inter-relations between gauge theory, algebraic geometry, combinatorics and number theory exhibit themselves in the form of plethystics and syzygies.

We present recent progress on the solution of WZW models based on type I supergroups. The spectrum is derived in the minisuperspace limit and extrapolated to the full WZW model. The main feature is the occurence of indecomposable non-chiral representations which are responsible for the logarithmic behaviour of correlation functions. The talk will consist of three parts: 1. Representation theory of Lie superalgebras, 2. general type I supergroup WZW models and 3. particularities of the PSU(1,1/2) WZW model. If the audience has enough stamina we can also discuss certain aspects of special marginal deformations of the PSU(1,1/2) WZW model which describe AdS(3)xS(3) with mixed RR and NS fluxes.

Members of the Editorial Board of Classical and Quantum Gravity will be convening for their annual meeting in London in May and will be taking the opportunity to hold a one day conference to present and discuss their latest research. The meeting will cover the broad range of subjects represented on the Board. Some external speakers have also been invited. The details of the program are available here: http://www.mth.kcl.ac.uk/events/theorphysics/program-25-5-06.pdf (copy link into your browser).