F-theory at order α′ 3

De Sitter solutions have been recently conjectured to be incompatible with quantum gravity. In this paper we critically assess the progress and challenges of different mechanisms to obtain de Sitter vacua in string compactifications and compare them to quintessence models. We argue that, despite recent criticisms, de Sitter models reached a level of concreteness and calculational control which has been improving over time. On the other hand, building string models of quintessence appears to be more challenging and requires additional fine‐tuning. We discuss the tension between the swampland conjecture and the Higgs potential and find examples which can evade fifth‐force bounds even if they seem very hard to realise in string theory. We also comment on the tension with low‐redshift data and explore ultra‐light axions from string theory as dark energy candidates.

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“…[] showed that

N = 1

O (α^{' 2})

corrections to the effective action give rise to moduli redefinitions, while ref. [] found that

N = 1

O (α^{' 3})

effects produce a shift of the CY Euler number term. Moreover, ref.…”

Section: De Sitter In String Theorymentioning

confidence: 99%

De Sitter vs Quintessence in String Theory

Cicoli

Alwis

Maharana

et al. 2018

Fortschritte der Physik

187

223

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“…where V is the Einstein-frame CY volume in string units, K α is an O(α 3 ) correction which depends just on the overall volume V [41][42][43], K gs contains both O(g 2 s α 2 ) and O(g 2 s α 4 ) string loop effects which depend on all T -moduli [33,37,38], while W 0 is the flux superpotential which can be considered as constant after complex structure and dilaton stabilisation.…”

Section: A Brief Reviewmentioning

confidence: 99%

“…Note that genuinely N = 1 O(α 3 ) corrections give rise to an effective Euler number by shifting χ(X) → χ eff = χ(X) + 2 X D 3 O7 , where D O7 is the two-form dual to the divisor wrapped by the O7-plane [42].…”

Section: Higher Derivative Effectsmentioning

confidence: 99%

Global embedding of fibre inflation models

Cicoli

Muia

Shukla

2016

J. High Energ. Phys.

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We present concrete embeddings of fibre inflation models in globally consistent type IIB Calabi-Yau orientifolds with closed string moduli stabilisation. After performing a systematic search through the existing list of toric Calabi-Yau manifolds, we find several examples that reproduce the minimal setup to embed fibre inflation models. This involves Calabi-Yau manifolds with h 1,1 = 3 which are K3 fibrations over a P 1 base with an additional shrinkable rigid divisor. We then provide different consistent choices of the underlying brane set-up which generate a non-perturbative superpotential suitable for moduli stabilisation and string loop corrections with the correct form to drive inflation. For each Calabi-Yau orientifold setting, we also compute the effect of higher derivative contributions and study their influence on the inflationary dynamics.

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“…Since such CY threefolds with the positive Euler number account for half of the whole CY threefolds in the sense of mirror symmetry, the CYs with the positive Euler number are not so restricted manifolds, but generic. The O7-plane contribution will also help us to change the number of CY Euler number in a weak coupling limit [21]. In Secs.…”

Section: B Stabilization Of Overall Volume Modulusmentioning

confidence: 99%

Radiative Kähler moduli stabilization

et al. 2018

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We propose a new type of Kähler moduli stabilization mechanisms in type IIB superstring theory on Calabi-Yau manifolds with the positive Euler number. The overall Kähler modulus can be perturbatively stabilized by radiative corrections due to sparticles. Its minimum is the anti-de Sitter vacuum, where supersymmetry is broken. We can uplift it to the de Sitter vacuum by introducing anti-D-branes, keeping the modulus stabilized. Although our numerical results depend on the choice of the cutoff scale and degeneracies of sparticles, at any rate there exist the parameter spaces where the masses of Kaluza-Klein and stringy modes are larger than the cutoff scale. Furthermore, this stabilization scenario predicts an ultralight axion.

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F-theory at order α′ 3

Cited by 62 publications

References 68 publications

De Sitter vs Quintessence in String Theory

De Sitter vs Quintessence in String Theory

Global embedding of fibre inflation models

Radiative Kähler moduli stabilization

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