Monodromy charge in D7-brane inflation

In axion monodromy inflation, traversing N axion periods corresponds to discharging N units of a quantized charge. In certain models with moving D7-branes, such as Higgs-otic inflation, this monodromy charge is D3-brane charge induced on the D7-branes. The stress-energy of the induced charge affects the internal space, changing the inflaton potential and potentially limiting the field range. We compute the backreaction of induced D3-brane charge in Higgs-otic inflation. The effect on the nonperturbative superpotential is dramatic even for N = 1, and may preclude large-field inflation in this model in the absence of a mechanism to control the backreaction.

$$\alpha $$-attractor from superconformal E-models in brane inflation

In the large extra dimensional braneworld inflation, Friedmann equation is modified to include a quadratic term in energy density with an additional parameter $$\lambda $$λ called brane tension in addition to the usual linear term. The high energy brane corrections modify the slow-roll parameters and affect the behaviour of inflation. We analyse the superconformal inflation for E-models and find that there exist $$\alpha $$α-attractors in brane inflation. The predictions for the scalar spectral index $$n_s$$ns and the tensor-to-scalar ratio r are computed numerically, and approximate analytic formulas in the high energy limit have been given for the observable $$n_s$$ns and r. The constraints on the model parameters are obtained by using Planck 2018 and BICEP2 observational data.