March 20, 2008 | Eva Silverstein and Alexander Westphal
Eva Silverstein and Alexander Westphal present a mechanism for large-field inflation in string theory, leading to gravitational wave signatures. They consider compactifications on twisted tori, where the monodromy of D-branes moving in circles on the manifold extends the field range. For Nil manifolds, they obtain a leading inflationary potential proportional to \(\phi^{2/3}\), yielding predictions for the tilt of the power spectrum and the tensor-to-scalar ratio, \(n_s \approx 0.98\) and \(r \approx 0.04\) with 60 e-foldings of inflation. They also discuss a variant with a potential proportional to \(\phi^{2/5}\). The mechanism involves controlling corrections to the slow-roll parameters using additional symmetries. The paper includes detailed analyses of the dynamics of wrapped D4-branes, the curvature-induced inflaton potential, and the consistency with moduli stabilization and background geometry.Eva Silverstein and Alexander Westphal present a mechanism for large-field inflation in string theory, leading to gravitational wave signatures. They consider compactifications on twisted tori, where the monodromy of D-branes moving in circles on the manifold extends the field range. For Nil manifolds, they obtain a leading inflationary potential proportional to \(\phi^{2/3}\), yielding predictions for the tilt of the power spectrum and the tensor-to-scalar ratio, \(n_s \approx 0.98\) and \(r \approx 0.04\) with 60 e-foldings of inflation. They also discuss a variant with a potential proportional to \(\phi^{2/5}\). The mechanism involves controlling corrections to the slow-roll parameters using additional symmetries. The paper includes detailed analyses of the dynamics of wrapped D4-branes, the curvature-induced inflaton potential, and the consistency with moduli stabilization and background geometry.