Collision of spinning black holes in the close limit

In this paper we consider the collision of spinning holes using first order perturbation theory of black holes (Teukolsky formalism). With these results (along with ones, we published in the past) one can predict the properties of the gravitational waves radiated from the late stage inspiral of two spinning, equal mass black holes. Also we note that the energy radiated by the head-on collision of two spinning holes with spins (that are equal and opposite) aligned along the common axis is more than the case in which the spins are perpendicular to the axis of the collision.Comment: 6 pages, 3 figures, submitted to PR

Chiral Lagrangians and the transition amplitude for radiative muon capture

The transition operator for the radiative capture of mesons mu minus by protons is constructed starting from a chiral Lagrangian of the N-pi-rho-a_1-omega system obtained within the approach of hidden local symmetries. The transition operator is gauge invariant and satisfies exactly the CVC and PCAC equations.Comment: 11 pages, 1 figure, LaTex, feynman, submitted to Few-Body System

Late-time Kerr tails: generic and non-generic initial data sets, "up" modes, and superposition

Three interrelated questions concerning Kerr spacetime late-time scalar-field tails are considered numerically, specifically the evolutions of generic and non-generic initial data sets, the excitation of "up" modes, and the resolution of an apparent paradox related to the superposition principle. We propose to generalize the Barack-Ori formula for the decay rate of any tail multipole given a generic initial data set, to the contribution of any initial multipole mode. Our proposal leads to a much simpler expression for the late-time power law index. Specifically, we propose that the late-time decay rate of the $Y_{\ell m}$ spherical harmonic multipole moment because of an initial $Y_{\ell' m}$ multipole is independent of the azimuthal number $m$, and is given by $t^{-n}$, where $n=\ell'+\ell+1$ for $\ell<\ell'$ and $n=\ell'+\ell+3$ for $\ell\ge\ell'$. We also show explicitly that the angular symmetry group of a multipole does not determine its late-time decay rate.Comment: 12 pages, 13 figures, 4 tables. Substantially revised manuscrip

SOCIAL CONTRACTS, MARKETS AND EFFICIENCY -- GROUNDWATER IRRIGATION IN NORTH INDIA

This paper uses primary data to analyze the institutions and informal markets that govern groundwater allocation in the principal sugarcane belt of North India. In contrast to earlier literature, we find that the observed water trades result in efficient water allocation across farms. We interpret this and other stylized facts in terms of a simple bargaining model with limited inter-player transfers. Poor functioning of the power sector leads to reduced pumping and a water supply constraint. Simulations show that power supply reform can significantly increase farm yields, be financed out of the increased farm profits, and provide an instrument to use for attaining intertemporal efficiency in water allocation.water markets, market structure, water production function.

Scenarios of energy efficiency and CO2 emissions reduction potential in the buildings sector in China to year 2050

As China’s rapid urbanization continues and urban dwellers become more affluent, energy use in buildings is expected to grow. To understand how this growth can be slowed, we explore four scenarios for Chinese buildings, ranging from a high-energy-demand scenario with no new energy policies to lowest energy demand under a techno-economic-potential scenario that assumes full deployment of cost-effective efficient and renewable technologies by 2050. We show that, in the high energy demand scenario, building energy demand has an average annual growth rate of about 2.8%, with slower growth rates in the other three scenarios. In all scenarios, CO2 emissions grow slower than energy, with building CO2 peaking around 2045 in the high energy demand scenario, and as early as 2030 in the techno-economic-potential scenario. We show that although various technological solutions, systems and practices can be very effective in minimizing building energy use, rigorous policies are needed to overcome multiple implementation barriers

CONSERVATION CAPITAL AND SUSTAINABLE ECONOMIC GROWTH

This paper develops an endogenous growth model which links pollution to ineffective input-use, which can be reduced through conservation capital investment. It derives the conditions under which individual preferences for environmental quality and private investment in conservation capital can lead to non-decreasing environmental quality and balanced growth in an unregulated and in a regulated regime. In the absence of regulation, balanced growth can lead to improvement in environmental quality as long as the rate of growth is low. The extent to which the growth rate is low depends upon preference for environmental quality, interest and discount rates, productivity of conservation capital, and price of the polluting input. Under an emissions tax regime, sustainable balanced growth requires the interest rate to lie between the amenity value derived by consumers from environmental improvement and the marginal return to the firm due to the regenerative capacity of the environment. This implies that interest rate must be high enough to encourage consumers to forego consumption but low enough to constrain the productivity of conservation capital and restrain usage of the polluting input. The emissions tax is also shown to be equivalent to a pollution permit system or to a two-instrument scheme composed of a tax on polluting input and a subsidy on conservation capital investment.Environmental Economics and Policy, International Development,

Massive scalar field instability in Kerr spacetime

We study the Klein-Gordon equation for a massive scalar field in Kerr spacetime in the time-domain. We demonstrate that under conditions of super-radiance, the scalar field becomes unstable and its amplitude grows without bound. We also estimate the growth rate of this instability.Comment: 10 pages, 5 figure