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'

Heat-kernel expansion and counterterms of the Faddeev-Popov determinant in Coulomb and Landau gauge

The Faddeev-Popov determinant of Landau gauge in d dimensions and Coulomb gauge in d+1 dimensions is calculated in the heat-kernel expansion up to next-to-leading order. The UV-divergent parts in d=3,4 are isolated and the counterterms required for a non-perturbative treatment of the Faddeev-Popov determinant are determined.Comment: 7 page

Potencial da fruticultura irrigada nos tabuleiros costeiros.

O Nordeste brasileiro apresenta condicoes excelente para a producao de frutas tropicais de boa qualidade, considerando-se seus aspectos ecologicos, a disponibilidade de area e mao-de-obra, alem das perspectivas favoraveis dos mercados internos e externos de frutas. Por muito tempo, a fruticultura do Nordeste concentrou-se nos Tabuleiros Costeiros, em grande parte situados na Zona da Mata e representando cerca de 8% do territorio nordestino. Nesta regiao, o cultivo de fruteiras e as acoes de pesquisa voltada para a fruticultura tradicionalmente nao lancavam mao da irrigacao. So a partir da decada de 1990 este recurso tecnologico passou a ser usado com frequencia cada vez maior, dada a ocorrencia de um periodo mais ou menos prolongado de deficiencia hidrica duraante a primavera e o verao afetando a produtividade e a vida util dos pomares e a qualidade dos frutos, alem de dificultar o deslocamento da producao para o periodo de entressafra, com precos mais alto para os frutos. Neste trabalho e analisado o potencial da fruticultura irrigada para as regioes dos Tabuleiros Costeiros, a sua viabilidade ecologica e economica, abordando-se tambem a contribuicao do Brasil e do Nordeste para a producao de frutas, as vantagens e os fatores limitantes a fruticultura e as perspectivas de mercado para frutas.bitstream/item/81401/1/Potencial-da-frut-Domingo-Reinhardt-Documentos-69-1996.pd

The Path Integral for 1+1-dimensional QCD

We derive a path integral expression for the transition amplitude in 1+1-dimensional QCD starting from canonically quantized QCD. Gauge fixing after quantization leads to a formulation in terms of gauge invariant but curvilinear variables. Remainders of the curved space are Jacobians, an effective potential, and sign factors just as for the problem of a particle in a box. Based on this result we derive a Faddeev-Popov like expression for the transition amplitude avoiding standard infinities that are caused by integrations over gauge equivalent configurations.Comment: 16 pages, LaTeX, 3 PostScript figures, uses epsf.st

Variational solution of the Yang-Mills Schr\"odinger equation 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. A coupled set of Schwinger-Dyson equations for the gluon and ghost propagators in the Yang-Mills vacuum as well as for the curvature of gauge orbit space is derived and solved in one-loop approximation. We find an infrared suppressed gluon propagator, an infrared singular ghost propagator and a almost linearly rising confinement potential.Comment: 24 pages, revtex, 13 figure

A diquark model for baryons containing one heavy quark

We present a phenomenological ansatz for coupling a heavy quark with two light quarks to form a heavy baryon. The heavy quark is treated in the heavy mass limit, and the light quark dynamics is approximated by propagating scalar and axial vector 'diquarks'. The resulting effective lagrangian, which incorporates heavy quark and chiral symmetry, describes interactions of heavy baryons with Goldstone bosons in the low energy region. As an application, the Isgur--Wise form factors are estimated.Comment: 9 pages + 8 figures, both as uuencoded PS, discussion of Bjorken limit (1 par + 1 fig) added, to appear in Z.Phys.

Quantum phase space picture of Bose-Einstein Condensates in a double well: Proposals for creating macroscopic quantum superposition states and a study of quantum chaos

We present a quantum phase space model of Bose-Einstein condensate (BEC) in a double well potential. In a two-mode Fock-state analysis we examine the eigenvectors and eigenvalues and find that the energy correlation diagram indicates a transition from a delocalized to a fragmented regime. Phase space information is extracted from the stationary quantum states using the Husimi distribution function. It is shown that the quantum states are localized on the known classical phase space orbits of a nonrigid physical pendulum, and thus the novel phase space characteristics of a nonrigid physical pendulum such as the $\pi$ motions are seen to be a property of the exact quantum states. Low lying states are harmonic oscillator like libration states while the higher lying states are Schr\"odinger cat-like superpositions of two pendulum rotor states. To study the dynamics in phase space, a comparison is made between a displaced quantum wavepacket and the trajectories of a swarm of points in classical phase space. For a driven double well, it is shown that the classical chaotic dynamics is manifest in the dynamics of the quantum states pictured using the Husimi distribution. Phase space analogy also suggests that a $\pi$ phase displaced wavepacket put on the unstable fixed point on a separatrix will bifurcate to create a superposition of two pendulum rotor states - a Schr\"odinger cat state (number entangled state) for BEC. It is shown that the choice of initial barrier height and ramping, following a $\pi$ phase imprinting on the condensate, can be used to generate controlled entangled number states with tunable extremity and sharpness.Comment: revised version, 13 pages, 13 figure

Nanosecond time transfer via shuttle laser ranging experiment

A method is described to use a proposed shuttle laser ranging experiment to transfer time with nanosecond precision. All that need be added to the original experiment are low cost ground stations and an atomic clock on the shuttle. It is shown that global time transfer can be accomplished with 1 ns precision and transfer up to distances of 2000 km can be accomplished with better than 100 ps precision