The Yang-Mills vacuum in Coulomb gauge

The Yang-Mills Schr\"odinger equation is solved in Coulomb gauge for the vacuum by the variational principle using an ansatz for the wave functional, which is strongly peaked at the Gribov horizon. We find an infrared suppressed gluon propagator, an infrared singular ghost propagator and an almost linearly rising confinement potential. Using these solutions we calculate the electric field of static color charge distributions relevant for mesons and baryons.Comment: 4 pages, 5 figures, Proceedings ``Confinement Conference Sardinia 2004'

Hamiltonian approach to Yang-Mills theory in Coulomb gauge

Recent results obtained within the Hamiltonian approach to continuum Yang-Mills theory in Coulomb gauge are reviewed.Comment: 7 pages, 2 figures, to appear in the ``Quark Confinement and the hadron spectrum VII'' (Portugal 2006) conference proceeding

Peer Effects, Financial Aid, and Selection of Students into Colleges and Universities: An Empirical Analysis

The goal of this paper is to develop predictions regarding market consequences of peer effects in higher education and to offer empirical evidence about the extent to which those predictions are borne out in the data. We develop a model in which colleges seek to maximize the quality of the educational experience provided to their students. From this model we deduce predictions about the hierarchy of schools that emerges in equilibrium, the allocation of students by income and ability among schools, and about the pricing policies that schools adopt. In the empirical analysis, we use both university-level data provided primarily by Petersons and student-level data from the National Postsecondary Student Aid Study obtained from the NCES. The findings of this paper suggest that there is a hierarchy of school qualities which is characterized by substantial stratification by income and ability. The evidence on pricing by ability is supportive of positive peer effects in educational achievement from high ability at the college level. However, the evidence on pricing also suggests that more highly ranked schools exercise some degree of market power. This is reflected in the substantial variation of price with income coupled with discounts to more able students that are modest at best.

School Finance Reform: Assessing General Equilibrium Effects

In 1994 the state of Michigan implemented one of the most comprehensive school finance reforms undertaken to date in any of the states. Understanding the effects of the reform is thus of value in informing other potential reform initiatives. In addition, the reform and associated changes in the economic environment provide an opportunity to assess whether a simple general equilibrium model can be of value in framing the study of such reform initiatives. In this paper, we present and use such a model to derive predictions about the effects of the reform on housing prices and neighborhood demographic compositions. Broadly, our analysis implies that the effects of the reform and changes in the economic environment are likely to have been reflected primarily in housing prices and only modestly on neighborhood demographics. We find that evidence for the Detroit metropolitan area from the decade encompassing the reform is largely consistent with the predictions of the model.

The Practice and Proscription of Affirmative Action in Higher Education:An Equilibrium Analysis

The paper examines the practice of affirmative action and consequences of its proscription on the admission and tuition policies of institutions of higher education in a general equilibrium. Colleges are differentiated ex ante by endowments and compete for students that differ by race, household income, and academic qualification. Colleges maximize a quality index that is increasing in mean academic score of students, educational resources per student, an income-diversity measure, and a racial-diversity measure. The pool of potential nonwhite students has distribution of income and academic score with lower means than that of whites. In benchmark equilibrium, colleges may condition admission and tuition on race. In a computational model calibrated using estimates from related research, equilibrium has colleges offer tuition discounts and admission preference to nonwhites to promote racial diversity. Equilibrium entails a quality hierarchy of colleges, so the model predicts practices and characteristics of colleges along the hierarchy. Proscription of affirmative action requires that admission and tuition policies are race blind. Colleges then use the informational content about race in income and academic score in reformulating their optimal policies. Admission and tuition policies are substantially modified in equilibrium of the computational model, and both races are significantly affected. Representation of nonwhites falls significantly in all colleges. The drop is particularly pronounced in the top third of the quality hierarchy of colleges.