12 papers · 1 filter
Determining the dual
Arjan Keurentjes
We study the R -> 0 limit for heterotic strings of either kind (Spin(32)/Z_2 or E_8 x E_8) compactified on a circle, in the presence of an arbitrary Wilson line. Though for generic…
Poincare Duality and G+++ algebra's
Arjan Keurentjes
Theories with General Relativity as a sub-sector exhibit enhanced symmetries upon dimensional reduction, which is suggestive of ``exotic dualities''. Upon inclusion of time-like di…
Towards an Effective Action for D-Branes
Arjan Keurentjes, Paul Koerber, Stijn Nevens +2
We introduce and review several indirect methods to calculate the effective action for a single D-brane or a set of coinciding D-branes.
Time-like T-duality algebra
Arjan Keurentjes
When compactifying M- or type II string-theories on tori of indefinite space-time signature, their low energy theories involve sigma models on E_{n(n)}/H_n, where H_n is a not nece…
E_11: Sign of the times
Arjan Keurentjes
We discuss the signature of space-time in the context of the E_11 -conjecture. In this setting, the space-time signature depends on the choice of basis for the ``gravitational sub-…
U-duality (sub-)groups and their topology
Arjan Keurentjes
We discuss some consequences of the fact that symmetry groups appearing in compactified (super-)gravity may be non-simply connected. The possibility to add fermions to a theory res…