More on the Nambu-Poisson M5-brane Theory: Scaling limit, background independence and an all order solution to the Seiberg-Witten map

We continue our investigation on the Nambu-Poisson description of M5-brane in a large constant C-field background (NP M5-brane theory) constructed in Refs.[1, 2]. In this paper, the low energy limit where the NP M5-brane theory is applicable is clarified. The background independence of the NP M5-brane theory is made manifest using the variables in the BLG model of multiple M2-branes. An all order solution to the Seiberg-Witten map is also constructed.Comment: expanded explanations, minor corrections and typos correcte

Constrained superfields on metastable anti-D3-branes

We study the effect of brane polarization on the supersymmetry transformations of probe anti-D3-branes at the tip of a Klebanov-Strassler throat geometry. As is well known, the probe branes can polarize into NS5-branes and decay to a supersymmetric state by brane-flux annihilation. The effective potential has a metastable minimum as long as the number of anti-D3-branes is small compared to the number of flux quanta. We study the reduced four-dimensional effective NS5-brane theory and show that in the metastable minimum supersymmetry is non-linearly realized to leading order, as expected for spontaneously broken supersymmetry. However, a strict decoupling limit of the higher order corrections in terms of a standard nilpotent superfield does not seem to exist. We comment on the possible implications of these results for more general low-energy effective descriptions of inflation or de Sitter vacua.Comment: 22 pages, 1 figure. v2: fixed typos, matches published versio

Decoupling in an expanding universe: backreaction barely constrains short distance effects in the cosmic microwave background

We clarify the status of trans-Planckian effects on the cosmic microwave background (CMB) anisotropy. We do so using the boundary effective action formalism of hep-th/ 0401164 which accounts quantitatively for the cosmological vacuum ambiguity. In this formalism we can clearly ( 1) delineate the validity of cosmological effective actions in an expanding universe. The corollary of the initial state ambiguity is the existence of an earliest time. The inability of an effective action to describe physics before this time demands that one sets initial conditions on the earliest time hypersurface. A calculation then shows that CMB anisotropy measurements are generically sensitive to high energy corrections to the initial conditions. ( 2) We compute the one-loop contribution to the stress tensor due to high energy physics corrections to an arbitrary cosmological initial state. We find that phenomenological bounds on the backreaction do not lead to strong constraints on the coefficient of the leading boundary irrelevant operator. Rather, we find that the power spectrum itself is the quantity most sensitive to initial state corrections. ( 3) The computation of the one-loop backreaction confirms arguments that irrelevant corrections to the Bunch - Davies initial state yield non-adiabatic vacua characterized by an energy excess at some earlier time. However, this excess only dominates over the classical background at times before the 'earliest time' at which the effective action is valid. We conclude that the cosmological effective action with boundaries is a fully self-consistent and quantitative approach to trans-Planckian corrections to the CMB