Wigner distribution, nonclassicality and decoherence of generalized and reciprocal binomial states

There are quantum states of light that can be expressed as finite superpositions of Fock states (FSFS). We demonstrate the nonclassicality of an arbitrary FSFS by means of its phase space distributions such as the Wigner function and the $Q$-function. The decoherence of the FSFS is studied by considering the time evolution of its Wigner function in amplitude decay and phase damping channels. As examples, we determine the nonclassicality and decoherence of generalized and reciprocal binomial states.Comment: 18 pages, 8 Figure

Reconstruction of SU(1,1) States

We show how group symmetries can be used to reconstruct quantum states. In our scheme for SU(1,1) states, the input field passes through a non-degenerate parametric amplifier and one measures the probability of finding the output state with a certain number (usually zero) of photons in each mode. The density matrix in the Fock basis is retrieved from the measured data by least squares method after singular value decomposition of the design matrix. Several illustrative examples involving the reconstruction of a pair coherent state, a Perelomov coherent state, and a coherent superposition of pair coherent states are considered.Comment: 8 pages, 5 figures, submitted to PR

Millers, Commission Agents and Collusion in Grain Auction Markets: Evidence from Basmati Auctions in North India

This paper undertakes structural estimation of asymmetric auction models in a market for basmati, and detects the presence of a cartel consisting of a large (in market share) local miller and commission agents purchasing for large distant millers. The contracts between the distant millers and their commission agents help to explain the specific form that collusion takes. Simulations indicate that (i) the cartel gains considerably by colluding, over the competitive outcome; (ii) however, sellers (farmers) do not lose significantly under collusion when the commission agents bid; (iii) a knowledgeable auctioneer would choose much higher starting prices for auctions when commission agents bid, compared with the observed starting prices. The paper also shows that efficient collusion, the form of collusion commonly assumed in the literature, does not explain the data well.Auctions, Cartels, Agricultural Markets.

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.

Comparison of lower order and higher order nonclassicality in photon added and photon subtracted squeezed coherent states

Nonclassical properties of photon added and photon subtracted squeezed coherent states have been compared with specific focus on the higher order nonclassicalities, such as higher order squeezing, higher order sub-Poissonian photon statistics, higher order antibunching. It is observed that both photon added and photon subtracted squeezed coherent states are highly nonclassical as they satisfy criteria for all of the above mentioned nonclassicalities and a set of other criteria including negativity of Wigner function, Klyshko's criterion and Agarwal's $(A_{3})$ parameter. Further, the amount of nonclassicality present in these two types of states has been compared quantitatively using a measure of nonclassicality known as nonclassical volume. Variation in the amount of nonclassicality with the number of photon(s) added/subtracted is also investigated, and it is found that the addition of photons makes the squeezed coherent state more nonclassical than what is done by the subtraction of photons.Comment: 23 pages 11 figure

A time frequency analysis of wave packet fractional revivals

We show that the time frequency analysis of the autocorrelation function is, in many ways, a more appropriate tool to resolve fractional revivals of a wave packet than the usual time domain analysis. This advantage is crucial in reconstructing the initial state of the wave packet when its coherent structure is short-lived and decays before it is fully revived. Our calculations are based on the model example of fractional revivals in a Rydberg wave packet of circular states. We end by providing an analytical investigation which fully agrees with our numerical observations on the utility of time-frequency analysis in the study of wave packet fractional revivals.Comment: 9 pages, 4 figure

Demonstration of fundamental mode only propagation in highly multimode fibre for high power EDFAs

The use of short lengths of large core phosphate glass fibre, doped with high concentrations of Er or Er:Yb represents an attractive route to achieving high power erbium doped fibre amplifiers (EDFAs) and lasers (EDFLs). With the aim of investigating the potential of achieving diffraction limited output from such large core fibres, we present experimental results of fundamental mode propagation through a 20 cm length of passive 300 micrometer core multimode fibre when the input is a well-aligned Gaussian beam. Through careful control of fibre geometry, input beam parameters and alignment, we measured an output M squared of 1.1 + - 0.05. The fibre had a numerical aperture of 0.389, implying a V number of 236.8. To our knowledge, this is the largest core fibre through which diffraction limited fundamental mode propagation has been demonstrated. Although the results presented here relate to undoped fibre, they do provide the practical basis for a new generation of EDFAs and EDFLs.Comment: 5 figure

The political economy of formal sector pay and employment in developing countries

Domestic labor market outcomes influence the direction and magnitude of the flow of international migration. When wages are low and jobs are scarce, workers tend to migrate to environments where jobs are available at higher wages. But as labor demand grows, a labor-exporting country may become a net labor importer. Such a"migration transition"- already much in evidence in East and Southeast Asian countries and beginning for skilled workers in India - is analogous to the demographic transition. The process of political economy described by the authors affects the level and growth of wages and of formal sector emmployment. So it is important for policymakers concerned about migration to high-income countries to take it into account. An efficient, flexible, responsive labormarket contributes to growth by creating an appropriate economic environment. In this respect, labor policy is like macroeconomic and trade policy. Unlike the accumulation of physical and human capital and technical progress, a well-functioning labor market is not itself a source of economic growth. Yet labor market pathologies, like macroeconomic mismanagement, can be extremely costly, severely constraining growth of output and employment and increasing inequality. Similarly, failure to adequately address the labor-market aspects of policy reform can result in the failure of other dimensions of reform. The smooth functioning of the labor market feeds on itself, enhancing the credibility of both workers and the elite. Conversely, poor labor market performance can also be self-reinforcing. Attempts to reform the labor market feeds on itself, enhancing the credibility of both workers and the elite. The payoff on labor reform can be high for both groups. The challenge is to find mechanisms whereby the credibility of both groups can be bolstered.Labor Policies,Environmental Economics&Policies,Banks&Banking Reform,Municipal Financial Management,Health Economics&Finance,Environmental Economics&Policies,Banks&Banking Reform,Municipal Financial Management,Health Economics&Finance,Labor Standards