Chromoelectric fields and quarkonium-hadron interactions at high energies

We develop a simple model to study the heavy quarkonium-hadron cross section in the high energy limit. The hadron is represented by an external electric color field (capacitor) and the heavy quarkonium is represented by a small color dipole. Using high energy approximations we compute the relevant cross sections, which are then compared with results obtained with other methods. Our calculations are presented in a pedagogical way accessible to undergraduate students.Comment: To appear in Physical Review C, 24 pages, 10 eps figure

Altruism and Relational Incentives in the Workplace

This paper studies how altruism between managers and employees affects relational incentive contracts. To this end we develop a simple dynamic principal-agent model where both players may have feelings of altruism or spite toward each other. The con- tract may contain two types of incentives for the agent to work hard: a bonus and a threat of dismissal. We find that altruism undermines the credibility of a threat of dis- missal but strengthens the credibility of a bonus. Among others, these two mechanisms imply that higher altruism sometimes leads to higher bonuses, while lower altruism may increase productivity and players utility in equilibrium

Optimal Incentive Contracts when Workers envy their Boss

A worker's utility may increase in his own income, but envy can make his utility decline with his employer's income. Such behavior may call for high-powered incentives, so that increased effort by the worker little increases the income of his employer. This paper employs a principal-agent model to study optimal incentive contracts for envious workers under various assumptions about the object and generality of envy. Envy amplifies the effect of incentives on effort and, therefore, increases optimal incentive pay. Moreover, envy can make profit-sharing optimal, even when the worker's effort is fully contractible. We discuss several applications of our theoretical work. For example, envy can explain why lower-level workers are awarded stock options, why incentive pay is usually lower in non-profit organizations, and higher in larger firms. Envy may also make governmental production of a good more efficient than private production

Education and Efficient Redistribution

Should education be subsidized for the purpose of redistribution? The usual argument against subsidies to education above the primary level is that the rich take up most education, so a subsidy would increase inequality. We show that there is a counteracting effect: an increase in the stock of human capital reduces the return to human capital and, therefore, pre-tax income inequality decreases. We consider a Walrasian world with perfect capital and insurance markets. Hence, in the absence of a strive for redistribution, the market generates the efficient level of investment in human capital. When there is a demand for redistribution, the general equilibrium effects on relative wages might make a subsidy to education an ingredient of a second-best optimal redistribution policy. Stimulating human capital formation results in a compression of the wage distribution, and hence reduces the need for distortionary redistributive taxation. We also study the political viability of education subsidies

Realization of the Optimal Universal Quantum Entangler

We present the first experimental demonstration of the ''optimal'' and ''universal'' quantum entangling process involving qubits encoded in the polarization of single photons. The structure of the ''quantum entangling machine'' consists of the quantum injected optical parametric amplifier by which the contextual realization of the 1->2 universal quantum cloning and of the universal NOT (U-NOT) gate has also been achieved.Comment: 10 pages, 3 figures, to appear in Physical Review

Subsidizing Enjoyable Education

We provide an explanation for why both college tuition and government grants to college students are typically means-tested. The critical idea is that attending college is both an investment good and a consumption good. The consumption benefit from education implies that, when tuition and grants are uniform, the marginal rich student is less smart than some poor people who choose not to attend college, thus reducing the social returns to education and increasing the college’s cost of education. Competition in the market for college education results in means-tested tuition. In addition, to maximize the social returns to education government should means-test grants. We thus provide a rationale for means-tested tuition and grants which relies neither on capital market imperfections nor on redistributive objectives

Lobbying of Firms by Voters

A firm may induce voters or elected politicians to support a policy it favors by suggesting that it is more likely to invest in a district whose voters or representatives support the policy. In equilibrium, no one vote may be decisive, and the policy may gain strong support though the majority of districts suffer from adoption of the program. When votes reveal information about the district, the firm's implicit promise or threat can be credible

Remote information concentration by GHZ state and by bound entangled state

We compare remote information concentration by a maximally entangled GHZ state with by an unlockable bound entangled state. We find that the bound entangled state is as useful as the GHZ state, even do better than the GHZ state in the context of communication security.Comment: 4 pages,1 figur

The desire for impact

This paper explores the meaning and implications of the desire by workers for impact. We find that this impact motive can make firms in a competitive labor market act as monopsonists, lead workers with the same characteristics but at different firms to earn different wages, may alleviate the hold-up problem in firm-specific investment, can make it profitable for an employer to give workers autonomy in effort or task choice, and can propagate shocks to unemployment

A note on bound entanglement and local realism

We show using a numerical approach that gives necessary and sufficient conditions for the existence of local realism, that the bound entangled state presented in Bennett et. al. Phys. Rev. Lett. 82, 5385 (1999) admits a local and realistic description. We also find the lowest possible amount of some appropriate entangled state that must be ad-mixed to the bound entangled state so that the resulting density operator has no local and realistic description and as such can be useful in quantum communication and quantum computation.Comment: 5 page