Natural Supergravity Inflation

We show that a single uncharged chiral superfield, canonically coupled to \mbox{$N=1$} supergravity with vanishing superpotential, naturally drives inflation in the early universe for a class of simple Kahler potentials. Inflation occurs due to the one-loop generation of a Kahler anomaly proportional to $\R^2$. The coefficient of this $\R^2$ term is of the correct magnitude to describe all aspects of an inflationary cosmology, including sufficient amplitude perturbations and reheating. Higher order terms proportional to $\R^n$ for $n \geq 3$ are naturally suppressed relative to the $\R^2$ term and, hence, do not destabilize the theory.Comment: 13 pages, CERN-TH.6685/92, UPR-0526

Brazil's Tropical Plan

This paper highlights the institutional features of the inflation process and contrasts two stabilization efforts in 1964-66 and in 1986.The inflation process in Brazil is highly institutional. It does not resemble hyperinflations where pricing and wage setting are geared to the exchange rate by the hour, making it possible to stop inflation by simply containing money creation and fixing the exchange rate. The two stabilization programs demonstrate that an incomes policy is an essential ingredient to non-recessionary stabilization. But they also show that demand restraint is inevitable if disinflation is to be viable. The 1964 program was gradualist and two-handed, relying on the supply side on wage repression. The 1986 plan was a heterodox shock treatment centered around an uncompromising price freeze and paying insufficient attention to the need for fiscal restraint.

Entropy Function for Heterotic Black Holes

We use the entropy function formalism to study the effect of the Gauss-Bonnet term on the entropy of spherically symmetric extremal black holes in heterotic string theory in four dimensions. Surprisingly the resulting entropy and the near horizon metric, gauge field strengths and the axion-dilaton field are identical to those obtained by Cardoso et. al. for a supersymmetric version of the theory that contains Weyl tensor squared term instead of the Gauss-Bonnet term. We also study the effect of holomorphic anomaly on the entropy using our formalism. Again the resulting attractor equations for the axion-dilaton field and the black hole entropy agree with the corresponding equations for the supersymmetric version of the theory. These results suggest that there might be a simpler description of supergravity with curvature squared terms in which we supersymmetrize the Gauss-Bonnet term instead of the Weyl tensor squared term.Comment: LaTeX file, 23 pages; v2: references added; v3: minor addition; v4: minor change