The Flux-Scaling Scenario: De Sitter Uplift and Axion Inflation

TL;DR

This work investigates uplifting flux-scaling vacua in type IIB string theory from AdS to Minkowski or de Sitter space using two mechanisms: an $\overline{{\rm D}3}$-brane uplift and a D-term uplift from geometric/non-geometric fluxes. It shows that the uplifted vacua lie on new scaling branches, preserving parametric control over moduli and mass scales, and explores their viability for axion monodromy inflation. A key finding is that with integer fluxes, the required hierarchy $M_s > M_{KK} > M_{\rm inf} > M_{\rm mod} > H_{\rm inf} > M_{\theta}$ is hard to achieve, but allowing rational flux values (via corrections to the complex-structure prepotential) can realize this hierarchy in explicit examples. The analysis combines analytic EFT reasoning with numerical studies to demonstrate possible inflationary dynamics, while noting that a full higher-dimensional string embedding of these vacua remains to be established.

Abstract

Non-geometric flux-scaling vacua provide promising starting points to realize axion monodromy inflation via the F-term scalar potential. We show that these vacua can be uplifted to Minkowski and de Sitter by adding an anti D3-brane or a D-term containing geometric and non-geometric fluxes. These uplifted non-supersymmetric models are analyzed with respect to their potential to realize axion monodromy inflation self-consistently. Admitting rational values of the fluxes, we construct examples with the required hierarchy of mass scales.

Figures (5)

• Figure 1: The scalar potential $V(\tau)$ in units of ${M_\text{Pl}^4 \over 4 \pi}$ for $\{s,v\}$ and the axions in their minimum. The fluxes are $h_0=10$, $h=q=1$, $f=5$ and $A$ is chosen to give a de Sitter minimum.
• Figure 2: Ratio of relevant mass scales for a) string scale over Kaluza-Klein scale and b) the Kaluza-Klein scale over the heaviest modulus. Fluxes are chosen rational with values $h = 1/220$, $\tilde{\mathfrak f} = 1/1810$, $\mathfrak f = 6/49$, $q = 1/8$, $g = 1/10$ and $p = 1/10000$.
• Figure 3: Vev's of the saxionic moduli for a) $s$ and b) $\tau$ and $v$.
• Figure 4: Backreacted (blue line) and quadratic potential in units $\frac{M_{\rm Pl}^4}{4\pi}$ given by eq. \ref{['vback2']} for $h = 1/220$, $\tilde{\mathfrak f} = 1/1810$, $\mathfrak f = 6/49$, $q = 1/8$, $g = 1/10$, $p = 1/10000$ and $\lambda = 10$.
• Figure 5: Backreacted (blue line) and quadratic potential in units $\frac{M_{\rm Pl}^4}{4\pi}$ given by eq. \ref{['vback2']} for $h = 1/220$, $\tilde{\mathfrak f} = 1/1810$, $\mathfrak f = 6/49$, $q = 1/8$, $g = 1/10$, $p = 1/10000$ and $\lambda = 5$.