De Sitter from T-branes

TL;DR

Problem: realize metastable de Sitter vacua in type IIB Calabi-Yau compactifications with stabilized moduli. Approach: develop a 4D uplift mechanism from hidden D7-brane flux-induced FI-terms and provide a matching 8D T-brane construction in which ISD flux and worldvolume flux generate the uplift from the D7-brane action. Findings: the uplift term scales as $V_{up} \\sim c_{up} M_P^4 / cal V^{8/3}$ and can yield a dS minimum when combined with LVS moduli stabilization; the 8D analysis reproduces the same uplifting, with subleading flux-induced corrections suppressed by $ cal V^{-2/3}$. Significance: establishes a concrete bridge between 4D effective uplifting and higher-dimensional brane dynamics, offering a controlled pathway to de Sitter vacua and guiding future global compactifications with T-brane realizations.

Abstract

Hidden sector D7-branes with non-zero gauge flux are a generic feature of type IIB compactifications. A non-vanishing Fayet-Iliopoulos term induced by non-zero gauge flux leads to a T-brane configuration. Expanding the D7-brane action around this T-brane background in the presence of three-form supersymmetry breaking fluxes, we obtain a positive definite contribution to the moduli scalar potential which can be used as an uplifting source for de Sitter vacua. In this way we provide a higher-dimensional understanding of known 4D mechanisms of de Sitter uplifting based on hidden sector F-terms which are non-zero because of D-term stabilisation.

Figures (2)

• Figure 1: Vacuum energy as a function of $g_s$ for $\lambda_s=\lambda_b=W_0=A_s=1$, $q_\phi=2 q_b$, $\zeta=2$ and $a_s=2\pi/N$. The intersection of the three curves with the abscissa shows the value of $g_s$ that gives a minimum where at leading order $\langle V\rangle=0$ for $N=2$ with ${\mathcal{V}} \simeq 7.5\cdot 10^7$ (green), $N=6$ with ${\mathcal{V}}\simeq 6.5\cdot 10^6$ (blue) and $N=10$ with ${\mathcal{V}}\simeq 3\cdot 10^4$ (red). Notice that we have plot $V_0\equiv \frac{18{\mathcal{V}}^3}{g_sW_0^2} \langle V_{\rm tot }\rangle$ instead of $\langle V_{\rm tot }\rangle$, as we are interested in the zeros.
• Figure 2: Vacuum energy ($V_0$) as a function of $g_s$ for $\lambda_s=\lambda_b=A_s=1$, $q_\phi=2 q_b$, $\zeta=2$ and $a_s=2\pi/6$. The intersection of the three curves with the abscissa shows the value of $g_s$ that gives a minimum where at leading order $\langle V\rangle=0$ for $W_0=1$ with ${\mathcal{V}} \simeq 6.5\cdot 10^6$ (blue), $W_0=10^{-5}$ with ${\mathcal{V}}\simeq 1.8\cdot 10^7$ (green) and $W_0=10^{-10}$ with ${\mathcal{V}}\simeq 3.5\cdot 10^7$ (red).