On de Sitter string vacua from anti-d3-branes in the large volume scenario

String theory realisations of the QCD axion are often said to belong to the anthropic window where the decay constant is around the GUT scale and the initial misalignment angle has to be tuned close to zero. In this paper we revisit this statement by studying the statistics of axion physics in the string landscape. We take moduli stabilisation properly into account since the stabilisation of the saxions is crucial to determine the physical properties of the corresponding axionic partners. We focus on the model-independent case of closed string axions in type IIB flux compactifications and find that their decay constants and mass spectrum feature a logarithmic, instead of a power-law, distribution. In the regime where the effective field theory is under control, most of these closed string axions are ultra-light axion-like particles, while axions associated to blow-up modes can naturally play the role of the QCD axion. Hence, the number of type IIB flux vacua with a closed string QCD axion with an intermediate scale decay constant and a natural value of the misalignment angle is only logarithmically suppressed. In a recent paper we found that this correlates also with a logarithmic distribution of the supersymmetry breaking scale, providing the intriguing indication that most, if not all, of the phenomenologically interesting quantities in the string landscape might feature a logarithmic distribution.

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“…This vacuum is AdS but there exist several mechanisms to uplift it to a dS solution [38][39][40][41].…”

Section: Jhep08(2021)059mentioning

confidence: 99%

Moduli stabilisation and the statistics of axion physics in the landscape

Broeckel

Cicoli

Maharana

et al. 2021

J. High Energ. Phys.

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“…In general, such an analysis would require a specific treatment which is beyond the reach of the present analysis, as our derivations depend crucially on the universal properties satisfied by the couplings of the EFT at LCS. However, in the specific case of conifold limits of the moduli space, it might be possible to make some progress following an analogous procedure to the one described in [130,131] (see also [132]). In those works, it was explicitly demonstrated that one can stabilise a subset of the complex structure moduli near a conifold point, while fixing the rest near the LCS point, i.e., at a conifold-LCS regime.…”

Section: Jhep04(2021)149mentioning

confidence: 99%

Towards a complete mass spectrum of type-IIB flux vacua at large complex structure

Sousa

Urkiola

Wachter

2021

J. High Energ. Phys.

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The large number of moduli fields arising in a generic string theory compactification makes a complete computation of the low energy effective theory infeasible. A common strategy to solve this problem is to consider Calabi-Yau manifolds with discrete symmetries, which effectively reduce the number of moduli and make the computation of the truncated Effective Field Theory possible. In this approach, however, the couplings (e.g., the masses) of the truncated fields are left undetermined. In the present paper we discuss the tree-level mass spectrum of type-IIB flux compactifications at Large Complex Structure, focusing on models with a reduced one-dimensional complex structure sector. We compute the tree-level spectrum for the dilaton and complex structure moduli, including the truncated fields, which can be expressed entirely in terms of the known couplings of the reduced theory. We show that the masses of this set of fields are naturally heavy at vacua consistent with the KKLT construction, and we discuss other phenomenologically interesting scenarios where the spectrum involves fields much lighter than the gravitino. We also derive the probability distribution for the masses on the ensemble of flux vacua, and show that it exhibits universal features independent of the details of the compactification. We check our results on a large sample of flux vacua constructed in an orientifold of the Calabi-Yau $$ {\mathbbm{W}\mathrm{\mathbb{P}}}_{\left[1,1,1,1,4\right]}^4 $$ W ℙ 1 1 1 1 4 4 . Finally, we also discuss the conditions under which the spectrum derived here could arise in more general compactifications.

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“…Note that neither the impossibility of obtaining de Sitter space from string theory, nor the instability of de Sitter due to infrared effects, have been rigorously established (see e.g. [35][36][37] and for works supporting the existence of effective field theory constructions of de Sitter in string theory, and [38] for a defence of the stability of de Sitter space).…”

Section: Jhep07(2021)206mentioning

confidence: 99%

Contracting cosmologies and the swampland

Bernardo

Brandenberger

2021

J. High Energ. Phys.

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We consider the cosmology obtained using scalar fields with a negative potential energy, such as employed to obtain an Ekpyrotic phase of contraction. Applying the covariant entropy bound to the tower of states dictated by the distance conjecture, we find that the relative slope of the potential |V′|/|V| is bounded from below by a constant of the order one in Planck units. This is consistent with the requirement to obtain slow Ekpyrotic contraction. We also derive a refined condition on the potential which holds near local minima of a negative potential.

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On de Sitter string vacua from anti-d3-branes in the large volume scenario

Cited by 41 publications

References 79 publications

Moduli stabilisation and the statistics of axion physics in the landscape

Moduli stabilisation and the statistics of axion physics in the landscape

Towards a complete mass spectrum of type-IIB flux vacua at large complex structure

Contracting cosmologies and the swampland

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