3,745 research outputs found
Tensor Hierarchy and Generalized Cartan Calculus in SL(3)SL(2) Exceptional Field Theory
We construct exceptional field theory for the duality group
SL(3)SL(2). The theory is defined on a space with 8 `external'
coordinates and 6 `internal' coordinates in the fundamental
representation, leading to a 14-dimensional generalized spacetime. The bosonic
theory is uniquely determined by gauge invariance under generalized external
and internal diffeomorphisms. The latter invariance can be made manifest by
introducing higher form gauge fields and a so-called tensor hierarchy, which we
systematically develop to much higher degree than in previous studies. To this
end we introduce a novel Cartan-like tensor calculus based on a covariant
nil-potent differential, generalizing the exterior derivative of conventional
differential geometry. The theory encodes the full or type IIB
supergravity, respectively.Comment: 49 page
A Monte Carlo exploration of threefold base geometries for 4d F-theory vacua
We use Monte Carlo methods to explore the set of toric threefold bases that
support elliptic Calabi-Yau fourfolds for F-theory compactifications to four
dimensions, and study the distribution of geometrically non-Higgsable gauge
groups, matter, and quiver structure. We estimate the number of distinct
threefold bases in the connected set studied to be . The
distribution of bases peaks around . All bases encountered
after "thermalization" have some geometric non-Higgsable structure. We find
that the number of non-Higgsable gauge group factors grows roughly linearly in
of the threefold base. Typical bases have isolated gauge
factors as well as several larger connected clusters of gauge factors with
jointly charged matter. Approximately 76% of the bases sampled contain
connected two-factor gauge group products of the form SU(3)SU(2), which
may act as the non-Abelian part of the standard model gauge group.
SU(3)SU(2) is the third most common connected two-factor product group,
following SU(2)SU(2) and SU(2), which arise more frequently.Comment: 38 pages, 22 figure
Non-toric bases for elliptic Calabi-Yau threefolds and 6D F-theory vacua
We develop a combinatorial approach to the construction of general smooth
compact base surfaces that support elliptic Calabi-Yau threefolds. This extends
previous analyses that have relied on toric or semi-toric structure. The
resulting algorithm is used to construct all classes of such base surfaces
with and all base surfaces over which there is an
elliptically fibered Calabi-Yau threefold with Hodge number . These two sets can be used todescribe all 6D F-theory models that
have fewer than seven tensor multiplets or more than 150 neutral scalar fields
respectively in their maximally Higgsed phase. Technical challenges to
constructing the complete list of base surfaces for all Hodge numbers are
discussed.Comment: 51 pages, 10 figure
The F-theory geometry with most flux vacua
Applying the Ashok-Denef-Douglas estimation method to elliptic Calabi-Yau
fourfolds suggests that a single elliptic fourfold gives
rise to F-theory flux vacua, and that the sum total
of the numbers of flux vacua from all other F-theory geometries is suppressed
by a relative factor of . The fourfold arises from a generic elliptic fibration over a specific toric threefold
base , and gives a geometrically non-Higgsable gauge group of
, of which we expect some
factors to be broken by G-flux to smaller groups. It is not possible to tune an
GUT group on any further divisors in , or even an
or , so the standard model gauge group appears to arise in this
context only from a broken factor. The results of this paper can either
be interpreted as providing a framework for predicting how the standard model
arises most naturally in F-theory and the types of dark matter to be found in a
typical F-theory compactification, or as a challenge to string theorists to
explain why other choices of vacua are not exponentially unlikely compared to
F-theory compactifications on .Comment: 19 pages, 2 figures, v3: minor corrections, clarifications,
references adde
Conical Defects, Black Holes and Higher Spin (Super-)Symmetry
We study the (super-)symmetries of classical solutions in the higher spin
(super-)gravity in AdS. We show that the symmetries of the solutions are
encoded in the holonomy around the spatial circle. When the spatial holonomies
of the solutions are trivial, they preserve maximal symmetries of the theory,
and are actually the smooth conical defects. We find all the smooth conical
defects in the , as well as in
and Chern-Simons gravity theories. In the bosonic higher spin
cases, there are one-to-one correspondences between the smooth conical defects
and the highest weight representations of Lie group. Furthermore we investigate
the higher spin black holes in and higher spin
(super-)gravity and find that they are only partially symmetric. In general,
the black holes break all the supersymmetries, but in some cases they preserve
part of the supersymmetries.Comment: 48 pages; more clarifications on conical defects in supersymmetric
cas
Black holes in Truncated Higher Spin AdS Gravity
We study the higher spin black holes in a truncated version of higher spin
gravity in . This theory contains only finite number of even spins
s=2,4,...,2N. We mainly focus on the simplest case, so-called (Type I and II)
spin gravity, which contains only spin 2 and spin 4 fields. This
spin gravity is as simple as spin 3 gravity, thus provides another
example to test various ideas on higher spin gravity. We find that the
asymptotical symmetry of this spin gravity is a classical
W(2,4)-symmetry. Moreover, we study the black hole solution with pure spin 4
hair and discuss its thermodynamics. One important feature of this black hole
is that its entropy could be written in compact forms. Furthermore, we
investigate a generated higher spin gravity. This higher spin gravity
only contains spin 2 and spin 6 fields which makes it different from other
kinds of higher spin gravity. We find the corresponding black hole with spin 6
hair, and discuss its thermodynamics analytically. It turns out that the black
holes with spin 4 or spin 6 hair constructed in this paper are the only black
holes with single higher spin hair, besides the spin 3 black hole found in
arXiv:1103.4304.Comment: 23 pages;minor revision, references added; published versio
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