Uncertainty relations for cosmological particle creation and existence of large fluctuations in reheating

We derive an uncertainty relation for the energy density and pressure of a quantum scalar field in a time-dependent, homogeneous and isotropic, classical background, which implies the existence of large fluctuations comparable to their vacuum expectation values. A similar uncertainty relation is known to hold for the field square since the field can be viewed as a Gaussian random variable. We discuss possible implications of these results for the reheating process in scalar field driven inflationary models, where reheating is achieved by the decay of the coherently oscillating inflaton field. Specifically we argue that the evolution after backreaction can seriously be altered by the existence of these fluctuations. For example, in one model the coherence of the inflaton oscillations is found to be completely lost in a very short time after backreaction starts. Therefore we argue that entering a smooth phase in thermal equilibrium is questionable in such models and reheating might destroy the smoothness attained by inflation.Comment: 6 pages, essay written for the Gravity Research Foundation 2011 Awards for Essays on Gravitation, Received Honorable Mentio

Power And Global Economic Institutions

What is the relationship between states\u27 economic power and their formal political power in multilateral economic institutions? Why do we see variation in states\u27 formal political power across economic institutions of the same era? In this book, Ayse Kaya examines these crucial under-explored questions, drawing on multiple theoretical traditions within international relations to advance a new approach of \u27adjusted power\u27. She explains how the economic shifts of our time, marked by the rise of Brazil, Russia, India, China and other emerging economies, have affected and will impact key multilateral economic institutions. Through detailed contemporary and historical analyses of the International Monetary Fund, the World Bank, the G20, and the International Trade Organization, Kaya shows that the institutional setting mediates the significance of the underlying distribution of economic power across states. The book presents both case studies and key statistics