22,529 research outputs found
Non-commutativity and non-associativity of the doubled string in non-geometric backgrounds
We use a T-duality invariant action to investigate the behaviour of a string
in non-geometric backgrounds, where there is a non-trivial global
patching or monodromy. This action leads to a set of Dirac brackets describing
the dynamics of the doubled string, with these brackets determined only by the
monodromy. This allows for a simple derivation of non-commutativity and
non-associativity in backgrounds which are (even locally) non-geometric. We
focus here on the example of the three-torus with H-flux, finding
non-commutativity but not non-associativity, and also comment on the relation
to the exotic brane, which shares the same monodromy.Comment: 31 pages, v2: refs added, corrections to sec 5, results updated, v3:
published version with additional discussion in sec
Conserved Currents of Double Field Theory
We find the conserved current associated to invariance under generalised
diffeomorphisms in double field theory. This can be used to define a
generalised Komar integral. We comment on its applications to solutions, in
particular to the fundamental string/pp-wave. We also discuss the current in
the context of Scherk-Schwarz compactifications. We calculate the current for
both the original double field theory action, corresponding to the NSNS sector
alone, and for the RR sector.Comment: 30 pages + appendix, v2: belated update to match published version
(typos + refs fixed, some minor comments added
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