scholarly journals Exotica or the failure of the strong cosmic censorship in four dimensions

2015 ◽  
Vol 12 (10) ◽  
pp. 1550121 ◽  
Author(s):  
Gábor Etesi
Keyword(s):  
Cosmological Constant ◽  
Cosmic Censorship ◽  
Twistor Theory ◽  
Wick Rotation ◽  
Four Dimensions ◽  
Precise Formulation ◽  
Ricci Flat ◽  
Lorentzian Metric ◽  
Strong Cosmic Censorship ◽  
Nonlinear Graviton

In this paper, a generic counterexample to the strong cosmic censor conjecture is exhibited. More precisely — taking into account that the conjecture lacks any precise formulation yet — first we make sense of what one would mean by a "generic counterexample" by introducing the mathematically unambigous and logically stronger concept of a "robust counterexample". Then making use of Penrose' nonlinear graviton construction (i.e. twistor theory) and a Wick rotation trick we construct a smooth Ricci-flat but not flat Lorentzian metric on the largest member of the Gompf — Taubes uncountable radial family of large exotic ℝ4's. We observe that this solution of the Lorentzian vacuum Einstein's equations with vanishing cosmological constant provides us with a sort of counterexample which is weaker than a "robust counterexample" but still reasonable to consider as a "generic counterexample". It is interesting that this kind of counterexample exists only in four dimensions.

scholarly journals Strong cosmic censorship in charged de sitter spacetime with scalar field non-minimally coupled to curvature

2019 ◽  
Vol 79 (11) ◽  
Author(s):  
Hong Guo ◽  
Hang Liu ◽  
Xiao-Mei Kuang ◽  
Bin Wang
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Cosmological Constant ◽  
Coupling Parameter ◽  
Cosmic Censorship ◽  
Charge Ratio ◽  
Cauchy Horizon ◽  
De Sitter ◽  
Critical Charge ◽  
Strong Cosmic Censorship

Abstract We examine the strong cosmic censorship in the Reissner–Nordstrom–de Sitter (RN-dS) black hole by investigating the evolution of a scalar field non-minimally coupled to the curvature. We find that for the stable RN-dS black hole, with the increase of the coupling parameter, the violation of the strong cosmic censorship occurs at a larger critical charge ratio. But such an increase of the critical charge is suppressed by the increase of the cosmological constant. Different from the minimal coupling situation, it is possible to accommodate $$\beta \ge 1$$β≥1 in the near extremal black hole when the scalar field is non-minimally coupled to curvature. $$\beta $$β here is defined as $$\beta \equiv -\frac{\mathrm {Im}\;\omega }{\kappa _{-}}$$β≡-Imωκ- where $$\kappa _{-}$$κ- is the surface gravity of Cauchy horizon and $$\omega $$ω is the frequency of quasinormal modes. The increase of the cosmological constant can allow $$\beta \ge 1$$β≥1 to be satisfied for even smaller value of the coupling parameter. The existence of $$\beta \ge 1$$β≥1 implies that the resulting curvature can continuously cross the Cauchy horizon.

scholarly journals Addendum to “Strong cosmic censorship: The nonlinear story”

2021 ◽  
Vol 103 (10) ◽  
Author(s):  
Raimon Luna ◽  
Miguel Zilhão ◽  
Vitor Cardoso ◽  
João L. Costa ◽  
José Natário
Keyword(s):  
Cosmic Censorship ◽  
Strong Cosmic Censorship

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.

The quantum consistency of the 12-dimensional theory

2016 ◽  
Vol 31 (04n05) ◽  
pp. 1650010
Author(s):  
Simon Davis
Keyword(s):  
Cosmological Constant ◽  
Moduli Space ◽  
Dimensional Reduction ◽  
Text Structure ◽  
Three Dimensions ◽  
Supersymmetric Theory ◽  
Particle Spectrum ◽  
Dimensional Theory ◽  
Cosmological Constant Problem ◽  
Four Dimensions

By considering the 12-dimensional superalgebra, inferences are drawn about the finiteness of the 12-dimensional theory unifying the superstring models. The dimensional reduction of the nonsupersymmetric theory in four dimensions to a supersymmetric action in three dimensions is established for the bosonic sector. It is found to be the quotient by [Formula: see text] of the integration over the fiber coordinate of a theory with [Formula: see text] supersymmetry. Consequently, a flow on the moduli space of Spin(7) manifolds from a [Formula: see text] structure with [Formula: see text] supersymmetry yielding a phenomelogically realistic particle spectrum to a [Formula: see text] holonomy manifold compatible with supersymmetry in three dimensions and a nonsupersymmetric action in four dimensions, solving the quantum cosmological constant problem, is proven to exist. The projection of the representations of the [Formula: see text] superalgebra of the 12-dimensional theory to four dimensions include nonperturbative string solitons that are more stable because the dynamics is described by supersymmetric theory with a higher degree of finiteness.

scholarly journals Strong cosmic censorship: taking the rough with the smooth

2018 ◽  
Vol 2018 (10) ◽  
Author(s):  
Oscar J. C. Dias ◽  
Harvey S. Reall ◽  
Jorge E. Santos
Keyword(s):  
Cosmic Censorship ◽  
Strong Cosmic Censorship

Supersymmetric quantum field theory (QFT): Introduction

2021 ◽  
pp. 656-669
Author(s):  
Jean Zinn-Justin
Keyword(s):  
Cosmological Constant ◽  
Particle Physics ◽  
Vector Fields ◽  
Hadron Collider ◽  
Large Mass ◽  
Momentum Tensor ◽  
Fine Tuning ◽  
Four Dimensions ◽  
New Feature ◽  
The Masses

Supersymmetry has been proposed, in particular as a principle to solve the so-called fine-tuning problem in particle physics by relating the masses of scalar particles (like Higgs fields) to those of fermions, which can be protected against ‘large’ mass renormalization by chiral symmetry. However, supersymmetry is, at best, an approximate symmetry broken at a scale beyond the reach of a large hadron collider (LHC), because the possible supersymmetric partners of known particles have not been discovered yet (2020) and thus, if they exist, must be much heavier. Exact supersymmetry would also have implied the vanishing of the vacuum energy and thus, of the cosmological constant. The discovery of dark energy has a natural interpretation as resulting from a very small cosmological constant. However, a naive model based on broken supersymmetry would still predict 60 orders of magnitude too large a value compared to 120 orders of magnitude otherwise. Gauging supersymmetry leads naturally to a unification with gravity, because the commutators of supersymmetry currents involve the energy momentum tensor. First, examples of supersymmetric theories involving scalar superfields, simple generalizations of supersymmetric quantum mechanics (QM) are described. The new feature of supersymmetry in higher dimensions is the combination of supersymmetry with spin, since fermions have spins. In four dimensions, theories with chiral scalar fields and vector fields are constructed.

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