Warm inflationary dynamics is shown to satisfy both the slow-roll and density perturbation constraints for mφ ≫ H or equivalently η ≫ 1 and for inflaton field amplitudes much below the Planck scale, 〈φ〉 < mpl. I start by reviewing the two types of inflation dynamics, isentropic or cold inflation and nonisentropic or warm inflation. In the former, inflation occurs without radiation production, w...

The fact that U.S. inflation has been remarkably low and stable over the past two decades prompts questions as to whether or not inflation persistence has changed to a lower level too. This paper employs the recently developed structural stability test with multiple regime shifts to model U.S. inflation dynamics over the past half century. Our empirical results suggest that the persistence of i...

Dissipative scalar quantum field theory is examined at zero temperature. Estimates of radiation production are given. Relevance of the results to supercooled and warm inflation are discussed. To appear in Proceeding, PASCOS-01, 2001 The basic picture of inflationary dynamics centers around a scalar field often called the inflaton. During the inflationary period, the potential energy of this fie...

We live in a very large, very old, and nearly (perhaps exactly) spatially flat universe. The universe we observe is, at least on large scales, remarkably homogeneous and isotropic. These attributes of our universe can be ascribed to a period of very rapid expansion, or inflation, at some time during the very early history of the universe [1]. A sufficiently long epoch of primordial inflation le...

This paper develops a small open economy, sticky-price model with a role for current account dynamics in the transmission of shocks. I solve the stationarity problem of incomplete markets, open economy models by adopting an overlapping-generations structure. I model nominal rigidity by assuming that firms face costs of output price inflation volatility. Markup dynamics affect labor demand and i...

In running mass inflation and hybrid inflation models it is possible that the inflaton field will fragment into non-topological solitons, resulting in a highly inhomogeneous post-inflation era prior to reheating. In supersymmetric models with a conventional homogeneous post-inflation era, the dynamics of flat direction scalars are determined by cH corrections to the mass squared terms (where |c...

Recently, a model of inflation using non-minimally coupled massive vector fields has been proposed. For a particular choice of non-minimal coupling parameter and for a flat FRW model, the model is reduced to the model of chaotic inflation with massive scalar field. We study the effect of non-zero curvature of the universe on the onset of vector inflation. We find that in a curved universe the d...

We compute the primordial scalar, vector and tensor metric perturbations arising from quantum field inflation. Quantum field inflation takes into account the nonperturbative quantum dynamics of the inflaton consistently coupled to the dynamics of the (classical) cosmological metric. For chaotic inflation, the quantum treatment avoids the unnatural requirements of an initial state with all the e...

Phillips curves are central to discussions of inflation dynamics and monetary policy. New Keynesian Phillips curves describe how past inflation, expected future inflation, and a measure of real marginal cost or an output gap drive the current inflation rate. This paper studies the (potential) weak identification of these curves under generalized methods of moments (GMM) and traces this syndrome...

This article studies U.S. monthly inflation, inflation growth, and price level dynamics from January 1967 to September 2005. Two rolling samples are constructed to recover evidence about instability in inflation, inflation growth, and price level persistence and volatility. Evidence is presented that changes in inflation, inflation growth, and price level persistence and volatility coincide wit...