Expanding universe and dynamical compactification using Yang-Mills instantons

Kim, Kyung Kiu; Koh, Seoktae; Yang, Hyun Seok

doi:10.1007/jhep12(2018)085

Cited by 10 publications

(3 citation statements)

References 65 publications

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“…Let us solve the maximization problem in two steps. First we fix 12) and maximize Tr (F ij ) 2 under this constraint. Following the discussion given in ref.…”

Section: Subtlety In the Derivation And The New Interpretationmentioning

confidence: 99%

On the structure of the emergent 3D expanding space in the Lorentzian type IIB matrix model

Aoki

Hirasawa

Ito

et al. 2019

Progress of Theoretical and Experimental Physics

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The emergence of (3+1)-dimensional expanding space-time in the Lorentzian type IIB matrix model is an intriguing phenomenon which was observed in Monte Carlo studies of this model. In particular, this may be taken as a support to the conjecture that the model is a nonperturbative formulation of superstring theory in (9+1) dimensions. In this paper we investigate the space-time structure of the matrices generated by simulating this model and its simplified versions, and find that the expanding part of the space is described essentially by the Pauli matrices. We argue that this is due to an approximation used in the simulation to avoid the sign problem, which actually amounts to replacing e iS b by e βS b (β > 0) in the partition function, where S b is the bosonic part of the action. We also discuss the possibility of obtaining a regular space-time with the (3+1)-dimensional expanding behavior in the original model with the correct e iS b factor.

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“…Let us solve the maximization problem in two steps. First we fix 12) and maximize Tr (F ij ) 2 under this constraint. Following the discussion given in ref.…”

Section: Subtlety In the Derivation And The New Interpretationmentioning

confidence: 99%

On the structure of the emergent 3D expanding space in the Lorentzian type IIB matrix model

Aoki

Hirasawa

Ito

et al. 2019

Progress of Theoretical and Experimental Physics

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show abstract

“…For earlier proposed constructions of de Sitter space in string theory, see references [], and for a discussion of various constraints on realizing de Sitter vacua in string theory, see for example []. For additional followups to reference [], see references [].…”

Section: Introductionmentioning

confidence: 99%

F‐theory and Dark Energy

Heckman

Lawrie

Lin

et al. 2019

Fortschritte der Physik

125

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Motivated by its potential use as a starting point for solving various cosmological constant problems, we study F-theory compactified on the warped product R time × S 3 × Y 8 where Y 8 is a Spi n(7) manifold, and the S 3 factor is the target space of an SU (2) Wess-Zumino-Witten (WZW) model at level N. Reduction to M-theory exploits the abelian duality of this WZW model to an S 3 /Z N orbifold. In the large N limit, the untwisted sector is captured by 11D supergravity. The local dynamics of intersecting 7-branes in the Spi n(7) geometry is controlled by a Donaldson-Witten twisted gauge theory coupled to defects. At late times, the system is governed by a 1D quantum mechanics system with a ground state annihilated by two real supercharges, which in four dimensions would appear as "N = 1/2 supersymmetry" on a curved background. This leads to a cancellation of zero point energies in the 4D field theory but a split mass spectrum for superpartners of order m 4D ∼ √ M IR M UV specified by the IR and UV cutoffs of the model. This is suggestively close to the TeV scale in some scenarios. The classical 4D geometry has an intrinsic instability which can produce either a collapsing or expanding Universe, the latter providing a promising starting point for a number of cosmological scenarios. The resulting 1D quantum mechanics in the time direction also provides an appealing starting point for a more detailed study of quantum cosmology.

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“…references [] and there has recently been much discussion in the context of the Swampland conjecture for the absence of de Sitter space . For some recent examples of the literature see references [].…”

Section: Introductionmentioning

confidence: 99%

Pixelated Dark Energy

Heckman

Lawrie

Lin

et al. 2019

Fortschritte der Physik

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We study the phenomenology of a recent string construction with a quantum mechanically stable dark energy. A mild supersymmetry protects the vacuum energy but also allows O(10−100) TeV scale superpartner masses. The construction is holographic in the sense that the 4D spacetime is generated from “spacetime pixels” originating from five‐branes wrapped over metastable five‐cycles of the compactification. The cosmological constant scales as Λ∼1/N in the pixel number. An instability in the construction leads to cosmic expansion. This also causes more five‐branes to wind up in the geometry, leading to a slowly decreasing cosmological constant which we interpret as an epoch of inflation followed by (pre‐)heating when a rare event occurs in which the number of pixels increases by an order one fraction. The sudden appearance of radiation triggers an exponential increase in the number of pixels. Dark energy has a time varying equation of state with wa=−3normalΩm,0false(1+w0false)/2, which is compatible with current bounds, and could be constrained further by future data releases. The pixelated nature of the Universe also implies a large‐l cutoff on the angular power spectrum of cosmological observables with l max ∼Ofalse(Nfalse). We also use this pixel description to study the thermodynamics of de Sitter space, finding rough agreement with effective field theory considerations.

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Expanding universe and dynamical compactification using Yang-Mills instantons

Cited by 10 publications

References 65 publications

On the structure of the emergent 3D expanding space in the Lorentzian type IIB matrix model

On the structure of the emergent 3D expanding space in the Lorentzian type IIB matrix model

F‐theory and Dark Energy

Pixelated Dark Energy

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