scholarly journals Non-supersymmetric AdS6 and the swampland

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Fabio Apruzzi ◽  
G. Bruno De Luca ◽  
Gabriele Lo Monaco ◽  
Christoph F. Uhlemann
Keyword(s):  
String Theory ◽  
Cosmological Constant ◽  
Mass Scale ◽  
Scale Separation ◽  
Decay Channels ◽  
Type Iib String Theory ◽  
The Stability

Abstract We discuss infinite families of non-supersymmetric AdS6 solutions in Type IIB string theory. They are siblings of supersymmetric solutions which are associated with (p, q) 5-brane webs and holographically dual to 5d SCFTs engineered by those brane webs. The non-supersymmetric backgrounds carry identical 5-brane charges and are connected to the supersymmetric ones by RG flows. We study the stability of the non-supersymmetric solutions, identifying perturbative and non-perturbative decay channels for all the backgrounds explicitly available. We also identify likely decay mechanisms for solutions that have not been constructed explicitly but may be expected to exist based on brane web considerations. Finally, we exclude scale separation by constructing universal spin 2 modes with masses comparable to the mass-scale of the cosmological constant.

scholarly journals Small cosmological constants in string theory

2021 ◽  
Vol 2021 (12) ◽  
Author(s):  
Mehmet Demirtas ◽  
Manki Kim ◽  
Liam McAllister ◽  
Jakob Moritz ◽  
Andres Rios-Tascon
Keyword(s):  
String Theory ◽  
Strong Evidence ◽  
Scale Separation ◽  
Type Iib String Theory ◽  
High Degree ◽  
Cosmological Constants ◽  
Hierarchical Scale ◽  
Kaluza Klein

Abstract We construct supersymmetric AdS4 vacua of type IIB string theory in compactifications on orientifolds of Calabi-Yau threefold hypersurfaces. We first find explicit orientifolds and quantized fluxes for which the superpotential takes the form proposed by Kachru, Kallosh, Linde, and Trivedi. Given very mild assumptions on the numerical values of the Pfaffians, these compactifications admit vacua in which all moduli are stabilized at weak string coupling. By computing high-degree Gopakumar-Vafa invariants we give strong evidence that the α′ expansion is likewise well-controlled. We find extremely small cosmological constants, with magnitude < 10−123 in Planck units. The compactifications are large, but not exponentially so, and hence these vacua manifest hierarchical scale-separation, with the AdS length exceeding the Kaluza-Klein length by a factor of a googol.

scholarly journals On D-brane dynamics and moduli stabilization

2017 ◽  
Vol 32 (29) ◽  
pp. 1750150
Author(s):  
Noriaki Kitazawa
Keyword(s):  
String Theory ◽  
Fixed Points ◽  
Supersymmetry Breaking ◽  
Compact Space ◽  
Complex Structure ◽  
Simultaneous Presence ◽  
Moduli Stabilization ◽  
Type Iib String Theory ◽  
The Stability ◽  
Repulsive Forces

We discuss the effect of the dynamics of D-branes on moduli stabilization in type IIB string theory compactifications, with reference to a concrete toy model of [Formula: see text] orientifold compactification with fractional D3-branes and anti-D3-branes at orbifold fixed points. The resulting attractive forces between anti-D3-branes and D3-branes, together with the repulsive forces between anti-D3-branes and O3-planes, can affect the stability of the compact space. There are no complex structure moduli in [Formula: see text] orientifold, which should thus capture some generic features of more general settings where all complex structure moduli are stabilized by three-form fluxes. The simultaneous presence of branes and anti-branes brings along the breaking of supersymmetry. Non-BPS combinations of this type are typical of “brane supersymmetry breaking” and are a necessary ingredient in the KKLT scenario for stabilizing the remaining Kähler moduli. The conclusion of our analysis is that, while mutual D-brane interactions sometimes help Kähler moduli stabilization, this is not always the case.

scholarly journals 5d and 4d SCFTs: canonical singularities, trinions and S-dualities

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Cyril Closset ◽  
Simone Giacomelli ◽  
Sakura Schäfer-Nameki ◽  
Yi-Nan Wang
Keyword(s):  
String Theory ◽  
Field Theories ◽  
Flavor Symmetry ◽  
Crepant Resolution ◽  
Superconformal Field Theories ◽  
Hypersurface Singularities ◽  
Canonical Singularities ◽  
Type Iib String Theory ◽  
M Theory

Abstract Canonical threefold singularities in M-theory and Type IIB string theory give rise to superconformal field theories (SCFTs) in 5d and 4d, respectively. In this paper, we study canonical hypersurface singularities whose resolutions contain residual terminal singularities and/or 3-cycles. We focus on a certain class of ‘trinion’ singularities which exhibit these properties. In Type IIB, they give rise to 4d $$ \mathcal{N} $$ N = 2 SCFTs that we call $$ {D}_p^b $$ D p b (G)-trinions, which are marginal gaugings of three SCFTs with G flavor symmetry. In order to understand the 5d physics of these trinion singularities in M-theory, we reduce these 4d and 5d SCFTs to 3d $$ \mathcal{N} $$ N = 4 theories, thus determining the electric and magnetic quivers (or, more generally, quiverines). In M-theory, residual terminal singularities give rise to free sectors of massless hypermultiplets, which often are discretely gauged. These free sectors appear as ‘ugly’ components of the magnetic quiver of the 5d SCFT. The 3-cycles in the crepant resolution also give rise to free hypermultiplets, but their physics is more subtle, and their presence renders the magnetic quiver ‘bad’. We propose a way to redeem the badness of these quivers using a class $$ \mathcal{S} $$ S realization. We also discover new S-dualities between different $$ {D}_p^b $$ D p b (G)-trinions. For instance, a certain E8 gauging of the E8 Minahan-Nemeschansky theory is S-dual to an E8-shaped Lagrangian quiver SCFT.

scholarly journals Standard model from a supergravity model with a naturally small cosmological constant

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Shing Yan Li ◽  
Yu-Cheng Qiu ◽  
S.-H. Henry Tye
Keyword(s):  
String Theory ◽  
Standard Model ◽  
Cosmological Constant ◽  
Supersymmetry Breaking ◽  
Supersymmetric Standard Model ◽  
Degrees Of Freedom ◽  
Interaction Terms ◽  
Supersymmetric Version ◽  
The Standard Model ◽  
Linear Version

Abstract Guided by the naturalness criterion for an exponentially small cosmological constant, we present a string theory motivated 4-dimensional $$ \mathcal{N} $$ N = 1 non-linear supergravity model (or its linear version with a nilpotent superfield) with spontaneous supersymmetry breaking. The model encompasses the minimal supersymmetric standard model, the racetrack Kähler uplift, and the KKLT anti-D3-branes, and use the nilpotent superfield to project out the undesirable interaction terms as well as the unwanted degrees of freedom to end up with the standard model (not the supersymmetric version) of strong and electroweak interactions.

scholarly journals On supersymmetric AdS4 orientifold vacua

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Fernando Marchesano ◽  
Eran Palti ◽  
Joan Quirant ◽  
Alessandro Tomasiello
Keyword(s):  
String Theory ◽  
Cosmological Constant ◽  
Bianchi Identities ◽  
Expansion Parameter ◽  
First Order ◽  
Ricci Flat ◽  
Key Features ◽  
One To One ◽  
Calabi Yau Manifolds

Abstract In this work we study ten-dimensional solutions to type IIA string theory of the form AdS4 × X6 which contain orientifold planes and preserve $$ \mathcal{N} $$ N = 1 supersymmetry. In particular, we consider solutions which exhibit some key features of the four-dimensional DGKT proposal for compactifications on Calabi-Yau manifolds with fluxes, and in this sense may be considered their ten-dimensional uplifts. We focus on the supersymmetry equations and Bianchi identities, and find solutions to these that are valid at the two-derivative level and at first order in an expansion parameter which is related to the AdS cosmological constant. This family of solutions is such that the background metric is deformed from the Ricci-flat one to one exhibiting SU(3) × SU(3)-structure, and dilaton gradients and warp factors are induced.

scholarly journals The holographic conformal manifold of 3d $$ \mathcal{N} $$ = 2 S-fold SCFTs

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Nikolay Bobev ◽  
Friðrik Freyr Gautason ◽  
Jesse van Muiden
Keyword(s):  
String Theory ◽  
Three Dimensional ◽  
Parameter Family ◽  
Global Symmetry ◽  
Maximal Supergravity ◽  
All Solutions ◽  
Operator Spectrum ◽  
Type Iib String Theory ◽  
Two Parameter

Abstract We employ a non-compact gauging of four-dimensional maximal supergravity to construct a two-parameter family of AdS4 J-fold solutions preserving $$ \mathcal{N} $$ N = 2 supersymmetry. All solutions preserve $$ \mathfrak{u} $$ u (1) × $$ \mathfrak{u} $$ u (1) global symmetry and in special limits we recover the previously known $$ \mathfrak{su} $$ su (2) × $$ \mathfrak{u} $$ u (1) invariant $$ \mathcal{N} $$ N = 2 and $$ \mathfrak{su} $$ su (2) × $$ \mathfrak{su} $$ su (2) invariant $$ \mathcal{N} $$ N = 4 J-fold solutions. This family of AdS4 backgrounds can be uplifted to type IIB string theory and is holographically dual to the conformal manifold of a class of three-dimensional S-fold SCFTs obtained from the $$ \mathcal{N} $$ N = 4 T [U(N)] theory of Gaiotto-Witten. We find the spectrum of supergravity excitations of the AdS4 solutions and use it to study how the operator spectrum of the three-dimensional SCFT depends on the exactly marginal couplings.

The possibility of a stable flat dark energy-dominated Swiss-cheese brane-world universe

2020 ◽  
Vol 17 (05) ◽  
pp. 2050075
Author(s):  
Nasr Ahmed ◽  
Kazuharu Bamba ◽  
F. Salama
Keyword(s):  
Dark Energy ◽  
Cosmological Constant ◽  
Cosmological Models ◽  
Brane World ◽  
Fine Tuning ◽  
Energy Conditions ◽  
Late Time ◽  
Swiss Cheese ◽  
Black Strings ◽  
The Stability

In this paper, we study the possibility of obtaining a stable flat dark energy-dominated universe in a good agreement with observations in the framework of Swiss-cheese brane-world cosmology. Two different brane-world cosmologies with black strings have been introduced for any cosmological constant [Formula: see text] using two empirical forms of the scale factor. In both models, we have performed a fine-tuning between the brane tension and the cosmological constant so that the Equation of state (EoS) parameter [Formula: see text] for the current epoch, where the redshift [Formula: see text]. We then used these fine–tuned values to calculate and plot all parameters and energy conditions. The deceleration–acceleration cosmic transition is allowed in both models, and the jerk parameter [Formula: see text] at late-times. Both solutions predict a future dark energy-dominated universe in which [Formula: see text] with no crossing to the phantom divide line. While the pressure in the first solution is always negative, the second solution predicts a better behavior of cosmic pressure where the pressure is negative only in the late-time accelerating era but positive in the early-time decelerating era. Such a positive-to-negative transition in the evolution of pressure helps to explain the cosmic deceleration–acceleration transition. Since black strings have been proved to be unstable by some authors, this instability can actually reflect doubts on the stability of cosmological models with black strings (Swiss-cheese type brane-worlds cosmological models). For this reason, we have carefully investigated the stability through energy conditions and sound speed. Because of the presence of quadratic energy terms in Swiss-cheese type brane-world cosmology, we have tested the new nonlinear energy conditions in addition to the classical energy conditions. We have also found that a negative tension brane is not allowed in both models of the current work as the energy density will no longer be well defined.

scholarly journals A REVIEW OF INTEGRABLE DEFORMATIONS IN AdS/CFT

2007 ◽  
Vol 22 (13) ◽  
pp. 915-930 ◽  
Author(s):  
IAN SWANSON
Keyword(s):  
String Theory ◽  
Bethe Ansatz ◽  
Energy Spectra ◽  
Yang Mills ◽  
Twisted String ◽  
Pp Wave ◽  
Integrable Deformations ◽  
Type Iib String Theory ◽  
Bethe Equations ◽  
Wave Limit

Marginal β deformations of [Formula: see text] super-Yang–Mills theory are known to correspond to a certain class of deformations of the S5 background subspace of type IIB string theory in AdS5×S5. An analogous set of deformations of the AdS5 subspace is reviewed here. String energy spectra computed in the near-pp-wave limit of these backgrounds match predictions encoded by discrete, asymptotic Bethe equations, suggesting that the twisted string theory is classically integrable in this regime. These Bethe equations can be derived algorithmically by relying on the existence of Lax representations, and on the Riemann–Hilbert interpretation of the thermodynamic Bethe ansatz. This letter is a review of a seminar given at the Institute for Advanced Study, based on research completed in collaboration with McLoughlin.

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