37 research outputs found
Isometries of five-branes and T-duality
No full text© The Authors, published by EDP Sciences, 2018. T-duality chain starting from the NS5-brane is known to generate exotic backgrounds. These have been described as a DFT background whose orientation in the doubled space defines specific 10-dimensional solutions. The focus of this letter is at isometries of the corresponding background, their relation to the NS five-brane charge and the section constraint of DFT. This letter is based on the talk presented by the author at the conference QUARKS'18
On the Non-Abelian U-Duality of 11D Backgrounds
No full textIn this work, we generalise the procedure of the non-abelian T-duality based on a B-shift and a sequence of formal abelian T-dualities in non-isometric directions to 11-dimensional backgrounds. This consists of a C-shift followed by either a formal (abelian) U-duality transformation or taking an IIB section. By construction, this is a solution generating transformation. We investigate the restrictions and applicability of the procedure and find that it can provide supergravity solutions for the SL(5) exceptional Drinfeld algebra only when the isometry algebra of the sigma-model target space decomposes into a direct sum. This is consistent with examples known in the literature
The invariant action for solitonic 5-branes
No full textWe construct the full effective action including DBI and WZ terms for
solitonic 5-branes covariant under T-duality. The result is a completion of
results known in the literature to a full T-duality covariant expression. The
covariant WZ action includes previously omitted R-R terms. The obtained full
covariant effective action reproduces the one obtained by S-duality from the
D5-brane upon the correct choice of the covariant charge
Non-abelian U-duality at work
No full textNon-abelian U-duality originates from the construction of exceptional
Drinfel'd algebra (EDA), which extends the constriction of the classical
Drinfel'd double. This symmetry is a natural extension of Poisson--Lie
T-duality and is believed to be a symmetry of Type II string/M-theory or their
low-energy effective theories. In this paper, we consider non-abelian
U-dualities of 11- or 10-dimensional backgrounds starting with E EDA
with with vanishing trombone gauging. The latter guarantees that all
dual backgrounds satisfy the standard supergravity equations of motion. In
particular, when the duality includes a timelike T-duality, we obtain solutions
of M-theory or Type II background equations, as expected. Also starting
with coboundary EDA's we provide examples of generalised Yang--Baxter
deformations of M-theory and Type IIB backgrounds. The obtained results provide
explicit examples when non-abelian U-duality works well as a solution
generating transformation.Comment: 36
Exceptional field theory: SL(5)
No full textIn this work the exceptional field theory formulation of supergravity with SL(5) gauge group is considered. This group appears as a U-duality group of maximal supergravity. In the formalism presented the hidden global duality group is promoted into a gauge group of a theory in dimensions 7+number of extended directions. This work is a continuation of the series of works for and duality groups
Tri-vector deformations on compact isometries
No full textClassical Yang-Baxter equation governing bi-vector deformations of 10d
supergravity is known to have no solutions along non-abelian compact
isometries. By providing explicit examples we show that this is in contrast to
generalized Yang-Baxter equation governing tri-vector deformations of 11d
supergravity. We present deformations of the AdS7xS4 and flat backgrounds with
isometries generated by Killing vectors of a sphere. Isometries of the AdS
space-time are preserved by such deformations.Comment: 24 page
U-Dualities in Type II and M-Theory: A Covariant Approach
No full textIn this review, a short description of exceptional field theory and its application is presented. Exceptional field theories provide a U-duality covariant description of supergravity theories, allowing addressing relevant phenomena, such as non-geometricity. Some applications of the formalism are briefly described
U-dualities in Type II string theories and M-theory.
No full textPhDIn this thesis the recently developed duality covariant approach to string and Mtheory
is investigated. In this formalism the U-duality symmetry of M-theory or Tduality
symmetry of Type II string theory becomes manifest upon extending coordinates
that describe a background.
The effective potential of Double Field Theory is formulated only up to a boundary
term and thus does not capture possible topological effects that may come from a
boundary. By introducing a generalised normal we derive a manifestly duality covariant
boundary term that reproduces the known Gibbons-Hawking action of General Relativity,
if the section condition is imposed. It is shown that the full potential can be
represented as a sum of the scalar potential of gauged supergravity and a topological
term that is a full derivative. The latter is written totally in terms of the geometric
flux and the non-geometric Q-flux integrated over the doubled torus.
Next we show that the Scherk-Schwarz reduction of M-theory extended geometry
successfully reproduces known structures of maximal gauged supergravities. Local symmetries
of the extended space defined by a generalised Lie derivatives reduce to gauge
transformations and lead to the embedding tensor written in terms of twist matrices.
The scalar potential of maximal gauged supergravity that follows from the effective potential
is shown to be duality invariant with no need of section condition. Instead, this
condition, that assures the closure of the algebra of generalised diffeomorphisms, takes
the form of the quadratic constraints on the embedding tensor
O() enhanced double field theory
No full textInternational audienceDouble field theory yields a formulation of the low-energy effective action of bosonic string theory and half-maximal supergravities that is covariant under the T-duality group O(d, d) emerging on a torus T . Upon reduction to three spacetime dimensions and dualisation of vector fields into scalars, the symmetry group is enhanced to O(d+1, d+1). We construct an enhanced double field theory with internal coordinates in the adjoint representation of O(d + 1, d + 1). Its section constraints admit two inequivalent solutions, encoding in particular the embedding of D = 6 chiral and non-chiral theories, respectively. As an application we define consistent generalized Scherk-Schwarz reductions using a novel notion of generalized parallelization. This allows us to prove the consistency of the truncations of D = 6, and D = 6, supergravity on
Five-brane actions in double field theory
No full textAbstract
We construct an action for NSNS 5-branes which is manifestly covariant under O(d, d). This is done by doubling d of the spacetime coordinates which appear in the worldvolume action. By formulating the DBI part of the action in a manner similar to a “gauged sigma model”, only half the doubled coordinates genuinely appear. Our approach allows one to describe the full T-duality orbit of the IIB NS5 brane, the IIA KKM and their exotic relations in one formalism. Furthermore, by using ideas from double field theory, our action can be said to describe various aspects of non-geometric five-branes.</jats:p
