pinecone/core-2020-05-10-deduplication huggingface dataset:
Supergravity with Fayet-Iliopoulos terms and R-symmetry

The simplest examples of gauged supergravities are N=1 or N=2 theories with
Fayet-Iliopoulos (FI) terms. FI terms in supergravity imply that the R-symmetry
is gauged. Also the U(1) or SU(2) local symmetries of Kaehler and
quaternionic-Kaehler manifolds contribute to R-symmetry gauge fields. This
short review clarifies the relations.Comment: 9 pages; contribution to the proceedings of the EC-RTN Workshop 'The
  quantum structure of spacetime and the geometric nature of fundamental
  interactions', Kolymbari, Crete, 5-10/9/2004, to be published in Fortschritte
  der Physi
Aspects of WZW models at critical level

We consider non-compact WZW models at critical level (equal to the dual
Coxeter number) as tensionless limits of gravitational backgrounds in string
theory. Special emphasis is placed on the Euclidean black hole coset
SL(2,R)_k/U(1) when k=2. In this limit gravity decouples in the form of a
Liouville field with infinite background charge and the world-sheet symmetry of
the model becomes a truncated version of W_\infty without Virasoro generator.
This is regarded as manifestation of Langlands duality for the SL(2,R)_k
current algebra that relates small with large values of the level in the two
extreme limits. However, the physical interpretation of the SL(2,R)_k/U(1)
coset model below the self-dual value k=3 remains elusive including the
non-conformal theory at k=2.Comment: 11 pages, contribution to the proceedings of 37th International
  Symposium Ahrenshoop (Berlin, 2004
Numerical Results for U(1) Gauge Theory on 2d and 4d Non-Commutative
  Spaces

We present non-perturbative results for U(1) gauge theory in spaces, which
include a non-commutative plane. In contrast to the commutative space, such
gauge theories involve a Yang-Mills term, and the Wilson loop is complex on the
non-perturbative level. We first consider the 2d case: small Wilson loops
follows an area law, whereas for large Wilson loops the complex phase rises
linearly with the area. In four dimensions the behavior is qualitatively
similar for loops in the non-commutative plane, whereas the loops in other
planes follow closely the commutative pattern. In d=2 our results can be
extrapolated safely to the continuum limit, and in d=4 we report on recent
progress towards this goal.Comment: 9 pages, 7 figures, talk presented at "Ahrenshoop 2004
Gauged maximal supergravities and hierarchies of nonabelian
  vector-tensor systems

We describe generalizations of the manifestly E_{6(6)} covariant formulation
of five-dimensional gauged maximal supergravity with regard to the structure of
the vector and tensor fields. We indicate how the group-theoretical structures
that we discover seem to play a role in gauged supergravities in various
space-time dimensions.Comment: 8 pages, to be published in Fortsch. Phys., proc. of the 37-th
  International Symposium Ahrenshoop on the Theory of Elementary Particles.
  Corrections in eqs. (15) and (25
The Topological G2 String

We construct new topological theories related to sigma models whose target
space is a seven dimensional manifold of G_2 holonomy. We define a new type of
topological twist and identify the BRST operator and the physical states.
Unlike the more familiar six dimensional case, our topological model is defined
in terms of conformal blocks and not in terms of local operators of the
original theory. We also present evidence that one can extend this definition
to all genera and construct a seven-dimensional topological string theory. We
compute genus zero correlation functions and relate these to Hitchin's
functional for three-forms in seven dimensions. Along the way we develop the
analogue of special geometry for G_2 manifolds. When the seven dimensional
topological twist is applied to the product of a Calabi-Yau manifold and a
circle, the result is an interesting combination of the six dimensional A- and
B-models.Comment: 76 pages, 1 figure, typos correcte
New Phases of Thermal SYM and LST from Kaluza-Klein Black Holes

We review the recently found map that takes any static and neutral
Kaluza-Klein black hole, i.e. any static and neutral black hole on
Minkowski-space times a circle M^d x S^1, and maps it to a corresponding
solution for a non- and near-extremal brane on a circle. This gives a precise
connection between phases of Kaluza-Klein black holes and the thermodynamic
behavior of the non-gravitational theories dual to near-extremal branes on a
circle. In particular, for the thermodynamics of strongly-coupled
supersymmetric Yang-Mills theories on a circle we predict the existence of a
new non-uniform phase and find new information about the localized phase. We
also find evidence for the existence of a new stable phase of (2,0) Little
String Theory in the canonical ensemble for temperatures above its Hagedorn
temperature.Comment: 9 pages, Proceedings for RTN Workshop in Kolymbari, Crete, September
  5-10, 2004, and 37th International Symposium Ahrenshoop, Wernsdorf, August
  23-27, 200
The Radion in 5D Conformal SUGRA: Superspace Action

We shortly review our new superfield formalism in the framework of Fujita,
Kugo, Ohashi 5D conformal supergravity, in particular with an $S^1/Z_2$
orbifold. The radion of the fifth dimension is embedded in two related
superfields, a chiral and a general multiplet and is linked to the radion
superfield of rigid SUSY. The superspace action of the gauge sector is of the
Chern-Simons type. We also present the superspace action for hypermultiplets
and discuss the role of compensators. The presented formalism should be very
useful for applications. We demonstrate this for obtaining the RS solution.Comment: Talk presented at the Ahrenshoop'04 conference (Berlin, August 23-27,
  2004
Splitting strings and chains

We review a study of the semiclassical decay of macroscopic spinning strings
in AdS_5 x S^5 as well as its dual gauge theory description. The conservation
of the infinite tower of commuting charges in the semiclassical string
sigma-model description of the process suggests that the decay channel of
maximal probability should preserve integrability in the gauge theory.Comment: 8 pages, 6 figures; Contribution to the proceedings of the 37th
  International Symposium Ahrenshoop, Berlin, August 23-27, 200
Gravitational scattering of massless scalars in QFT and superstring
  theory

In this paper we perform the calculation of the gravitational scattering
amplitude for 4 massless scalars in quantum field theory and Type II
superstring theory. We show that the results agree, providing an example of how
gravity is incorporated in the superstring theory. During the calculation we
quantize gravitational action to derive graviton propagator and interaction
vertex with massless scalar. We also calculate general 3-point and 4-point
scattering amplitudes in SST for open and closed massless strings in NS sector.Comment: 28 pages, 5 figure
Heterotic strings on homogeneous spaces

We construct heterotic string backgrounds corresponding to families of
homogeneous spaces as exact conformal field theories. They contain left cosets
of compact groups by their maximal tori supported by NS-NS 2-forms and gauge
field fluxes. We give the general formalism and modular-invariant partition
functions, then we consider some examples such as SU(2)/U(1) ~ S^2 (already
described in a previous paper) and the SU(3)/U(1)^2 flag space. As an
application we construct new supersymmetric string vacua with magnetic fluxes
and a linear dilaton.Comment: JHEP style; 47 pages, one figur
The effective action of D-branes in Calabi-Yau orientifold
  compactifications

In this review article we study type IIB superstring compactifications in the
presence of space-time filling D-branes while preserving N=1 supersymmetry in
the effective four-dimensional theory. This amount of unbroken supersymmetry
and the requirement to fulfill the consistency conditions imposed by the
space-time filling D-branes lead to Calabi-Yau orientifold compactifications.
For a generic Calabi-Yau orientifold theory with space-time filling D3- or
D7-branes we derive the low-energy spectrum. In a second step we compute the
effective N=1 supergravity action which describes in the low-energy regime the
massless open and closed string modes of the underlying type IIB Calabi-Yau
orientifold string theory. These N=1 supergravity theories are analyzed and in
particular spontaneous supersymmetry breaking induced by non-trivial background
fluxes is studied. For D3-brane scenarios we compute soft-supersymmetry
breaking terms resulting from bulk background fluxes whereas for D7-brane
systems we investigate the structure of D- and F-terms originating from
worldvolume D7-brane background fluxes. Finally we relate the geometric
structure of D7-brane Calabi-Yau orientifold compactifications to N=1 special
geometry.Comment: LaTeX, 133 pages, Ph.D. Thesis (Advisor: Jan Louis); v2: references
  adde
The effective action of type II Calabi-Yau orientifolds

This article first reviews the calculation of the N = 1 effective action for
generic type IIA and type IIB Calabi-Yau orientifolds in the presence of
background fluxes by using a Kaluza-Klein reduction. The Kahler potential, the
gauge kinetic functions and the flux-induced superpotential are determined in
terms of geometrical data of the Calabi-Yau orientifold and the background
fluxes. As a new result, it is shown that the chiral description directly
relates to Hitchin's generalized geometry encoded by special odd and even forms
on a threefold, whereas a dual formulation with several linear multiplets makes
contact to the underlying N = 2 special geometry. In type IIB setups, the
flux-potentials can be expressed in terms of superpotentials, D-terms and,
generically, a massive linear multiplet. The type IIA superpotential depends on
all geometric moduli of the theory. It is reviewed, how type IIA orientifolds
arise as a special limit of M-theory compactified on specific G_2 manifolds by
matching the effective actions. In a similar spirit type IIB orientifolds are
shown to descend from F-theory on a specific class of Calabi-Yau fourfolds. In
addition, mirror symmetry for Calabi-Yau orientifolds is briefly discussed and
it is shown that the N = 1 chiral coordinates linearize the appropriate
instanton actions.Comment: 137 pages, Ph.D. Thesis (Advisor: Jan Louis), v2: references adde
Flux Compactification of M-theory on Compact Manifolds with Spin(7)
  Holonomy

At the leading order, M-theory admits minimal supersymmetric
compactifications if the internal manifold has exceptional holonomy. The
inclusion of non-vanishing fluxes in M-theory and string theory
compactifications induce a superpotential in the lower dimensional theory,
which depends on the fluxes. In this work, we verify the conjectured form of
this superpotential in the case of warped M-theory compactifications on Spin(7)
holonomy manifolds. We calculate the most general causal N=1 three-dimensional,
gauge invariant action coupled to matter in superspace and derive its component
form using Ectoplasmic integration theory. We also derive a perturbative set of
solutions which emerges from a warped compactification on a Spin(7) holonomy
manifold with non-vanishing flux for the M-theory field strength and we show
that in general the Ricci flatness of the internal manifold is lost. Using the
superpotential form we identify the supersymmetric vacua out of this general
set of solutions.Comment: Ph.D. Thesis - 131 pages, no figure
Effective Supergravity from the Weakly Coupled Heterotic String

The motivation for Calabi-Yau-like compactifications of the weakly coupled
$E_8\otimes E_8$ heterotic string theory, its particle spectrum and the issue
of dilaton stabilization are briefly reviewed. Modular invariant models for
hidden sector condensation and supersymmetry breaking are described at the
quantum level of the effective field theory. Their phenomenological and
cosmological implications, including a possible origin for R-parity, are
discussed.Comment: 17 pages, Talk presented at the Symposium in honor of Julius Wess,
  Jan. 10--11, 200
Uplifting the Iwasawa

The Iwasawa manifold is uplifted to seven-folds of either G_2 holonomy or
SU(3) structure, explicit new metrics for the same having been constructed in
this work. We uplift the Iwasawa manifold to a G_2 manifold through "size"
deformation (of the Iwasawa metric), via Hitchin's Flow equations, showing also
the impossibility of the uplift for "shape" and "size" deformations (of the
Iwasawa metric). Using results of [1], we also uplift the Iwasawa manifold to a
7-fold with SU(3) structure through "size" and "shape" deformations via
generalisation of Hitchin's Flow equations. For seven-folds with
SU(3)-structure, the result could be interpreted as M5-branes wrapping
two-cycles embedded in the seven-fold - a warped product of either a special
hermitian six-fold or a balanced six-fold with the unit interval. There can be
no uplift to seven-folds of SU(3) structure involving non-trivial "size" and
"shape" deformations (of the Iwasawa metric) retaining the "standard complex
structure" - the uplift generically makes one move in the space of almost
complex structures such that one is neither at the standard complex structure
point nor at the "edge". Using the results of [2] we show that given two "shape
deformation" functions, and the dilaton, one can construct a Riemann surface
obtained via Weierstrass representation for the conformal immersion of a
surface in R^l, for a suitable l, with the condition of having conformal
immersion being a quadric in CP^{l-1}.Comment: 27 pages, LaTeX; v4: (shorter [on referee's suggestion] version of
  this eprint) to appear in Fortsch. Phys. 200
Moduli Stabilization in the Heterotic/IIB Discretuum

We consider supersymmetric compactifications of type IIB and the weakly
coupled heterotic string with G resp.H-flux and gaugino condensation in a
hidden sector included. We point out that proper inclusion of the
non-perturbative effects changes the Hodge structure of the allowed fluxes in
type IIB significantly. In the heterotic theory it is known that, in contrast
to the potential read off from dimensional reduction, the effective
four-dimensional description demands for consistency a non-vanishing H^{2,1}
component if a H^{3,0} component is already present balancing the condensate.
The H^{2,1} component causes a non-Kahlerness of the underlying geometry whose
moduli space is, however, not well-understood. We show that the occurrence of
H^{2,1} might actually be avoided by using a KKLT-like two-step procedure for
moduli stabilization. Independently of the H^{2,1} issue one-loop corrections
to the gauge couplings were argued to cause a not well-controlled strong
coupling transition. This problem can be avoided as well when the effects of
world-sheet instantons are included. They will also stabilize the Kahler
modulus what was accomplished by H^{2,1} before.Comment: 30 pages, there was an error with refs. which disappeared in the 1st
  revised version (sorry!
Black Holes and Rings of minimal 5-dim. Supergravity

In this talk, I will summarize recent developments in 5-dimensional
supergravity. Apart from black ring solutions, we will discuss the way of
obtaining regular (bubbling) solutions with the same charges as black holes. We
outline the procedure for the solution in five and four dimensions. Finally we
explore the close relationship between 4- and 5-dimensional supersymmetric
stationary solutions.Comment: 9 pages, to appear in Proceedings of: RTN workshop: ``The quantum
  structure of space-time and the geometric nature of fundamental
  interactions'', Corfu, September 2005; improved ref
On Killing tensors and cubic vertices in higher-spin gauge theories

The problem of determining all consistent non-Abelian local interactions is
reviewed in flat space-time. The antifield-BRST formulation of the free theory
is an efficient tool to address this problem. Firstly, it allows to compute all
on-shell local Killing tensor fields, which are important because of their deep
relationship with higher-spin algebras. Secondly, under the sole assumptions of
locality and Poincare invariance, all non-trivial consistent deformations of a
sum of spin-three quadratic actions deforming the Abelian gauge algebra were
determined. They are compared with lower-spin cases.Comment: 10 pages. Based on a talk given by X.B. at the RTN Workshop
  ``Constituents, Fundamental Forces and Symmetries of the Universe'' (Corfu,
  20-26th September 2005). Contribution to the Proceeding
New results for AdS/CFT and beyond

We report on some recent results within the string/gauge theory
correspondence, both in the conformal and in the non conformal cases, for a
recently found class of N=1 dual pairs. These results provide the first cross
check of AdS/CFT and field theory techniques like a-maximization. Moreover,
they furnish new examples of cascading gauge theories and the first instance of
4d dynamical supersymmetry breaking embedded in the correspondenceComment: LateX, 11 pages, 2 figures. Contribution to the proceedings of the
  RTN meeting "Constituents, Fundamental Forces and symmetries of the
  Universe'', Corfu, Greece, 20-26 September 200
From Toric Geometry to Quiver Gauge Theory: the Equivalence of
  a-maximization and Z-minimization

AdS/CFT predicts a precise relation between the central charge a, the scaling
dimensions of some operators in the CFT on D3-branes at conical singularities
and the volumes of the horizon and of certain cycles in the supergravity dual.
We review how a quantitative check of this relation can be performed for all
toric singularities. In addition to the results presented in hep-th/0506232, we
also discuss the relation with the recently discovered map between toric
singularities and tilings; in particular, we discuss how to find the precise
distribution of R-charges in the quiver gauge theory using dimers technology.Comment: 13 pages, 4 figures; proceedings of the RTN workshop: ``Constituents,
  Fundamental Forces and Symmetries of the Universe'', Corfu, Greece, 20-26
  Sept. 200
Chronology Protection in AdS/CFT

We review the issue of chronology protection and show how string theory can
solve it in the half BPS sector of AdS/CFT. According to the LLM prescription,
half BPS excitations of AdS_5 x S^5 geometries in type IIB string theory can be
mapped into free fermion configurations. We show that unitarity of the theory
describing these fermions is intimately related to the protection of the
chronology in the dual geometries.Comment: 7 pages, 7 figures, contribution to the proceedings of the RTN
  workshop "Constituents, Fundamental Forces and Symmetries of the Universe",
  Corfu, Greece, 20-26 September 200
Fluxes, moduli fixing and MSSM-like vacua in Type IIA String Theory

We review some of the features of Type IIA compactifications in the presence
of fluxes. In particular, the case of $T^6/(\Omega (-1)^{F_L} \sigma)$
orientifolds with RR, NS and metric fluxes is considered. This has revealed to
possess remarkable properties such as vacua with all the closed string moduli
stabilized, null or negative contributions to the RR tadpoles or supersymmetry
on the branes enforced by the closed string background. In this way, Type IIA
compactifications with non trivial fluxes seem to constitute a new window into
the building of semi-realistic models in String Theory.Comment: 8 pages; Contribution to the proceedings of the RTN workshop
  "Constituents, Fundamental Forces and Symmetries of the Universe", Corfu,
  Greece, 20-26 September 2005; corrected typos, added reference
Electric Tachyon Inflation

We propose that under certain conditions the universal open string tachyon
can drive topological inflation in moduli stabilised frameworks. Namely, the
presence of electric field in the world volume of the D-brane can slow down its
decay leading to a phenomenological model of inflation. The conditions for
inflation to take place are difficult to satisfy in the standard warped
deformed conifold but easier to realise in other geometries.Comment: 8 pages; Contribution to the proceedings of the RTN workshop
  "Constituents, Fundamental Forces and Symmetries of the Universe", Corfu,
  Greece, 20-26 September 2005. v2: Typos corrected, reference adde
Instantons on D7 brane probes and AdS/CFT with flavour

Recent work on adding flavour to the generalized AdS/CFT correspondence is
reviewed. In particular, we consider instanton configurations on two coincident
D7 brane probes. These are matched to the Higgs branch of the dual field
theory. In AdS_5 x S^5, the instanton generates a flow of the meson spectrum.
For non-supersymmetric gravity backgrounds, the Higgs branch is lifted by a
potential, which has non-trivial physical implications. In particular these
configurations provide a gravity dual description of Bose-Einstein condensation
and of a thermal phase transition.Comment: 12 pages, 5 figures. Based on talk given by J. Erdmenger at the RTN
  Workshop``Constituents, Fundamental Forces and Symmetries of the
  Universe'',Corfu,Greece, 20-26th September 2005. Contribution to the
  Proceeding
Standard Model statistics of a Type II orientifold

We analyse four-dimensional, supersymmetric intersecting D-brane models in a
toroidal orientifold background from a statistical perspective. The
distribution and correlation of observables, like gauge groups and couplings,
are discussed. We focus on models with a Standard Model-like gauge sector,
derive frequency distributions for their occurence and analyse the properties
of the hidden sector.Comment: 9 pages, 9 figures; v2: typos corrected, one reference added;
  Contribution to the proceedings of the RTN workshop "Constituents,
  Fundamental Forces and Symmetries of the Universe", Corfu, Greece, 20-26 Sep
  200
Partition function of dyonic black holes in N=4 string theory

The dominant contribution to the semicanonical partition function of dyonic
black holes of N=4 string theory is computed for generic charges, generalizing
recent results of Shih and Yin. The result is compared to the black hole free
energy obtained from the conjectured relation to topological strings. If
certain perturbative corrections are included agreement is found to subleading
order. These corrections modify the conjectured relation and implement
covariance with respect to electric-magnetic duality transformations.Comment: 9 page
Renormalization-group flows and charge transmutation in string theory

We analyze the behaviour of heterotic squashed-Wess-Zumino-Witten backgrounds
under renormalization-group flow. The flows we consider are driven by
perturbation creating extra gauge fluxes. We show how the conformal point acts
as an attractor from both the target-space and world-sheet points of view. We
also address the question of instabilities created by the presence of closed
time-like curves in string backgroundsComment: Based on a talk given by D.O. at the RTN meeting "Constituents,
  Fundamental Forces and symmetries of the Universe'' in Corfu, Greece, 20-26
  September 200
Moduli Stabilization in Toroidal Type IIB Orientifolds

We discuss the first step in the moduli stabilization program a la KKLT for a
general class of resolved toroidal type IIB orientifolds. In particular, we
discuss their geometry, the topology of the divisors relevant for the D3-brane
instantons which can contribute to the superpotential, and some non--trivial
aspects of the orientifold action.Comment: 15 pages, 3 figures, contribution to the proceedings of the RTN
  workshop "Constituents, Fundamental Forces and Symmetries of the Universe",
  Corfu, Greece, 20-26 September 200