Succesful renormalization of a QCD-inspired Hamiltonian

The long standing problem of non perturbative renormalization of a gauge field theoretical Hamiltonian is addressed and explicitly carried out within an (effective) light-cone Hamiltonian approach to QCD. The procedure is in line with the conventional ideas: The Hamiltonian is first regulated by suitable cut-off functions, and subsequently renormalized by suitable counter terms to make it cut-off independent. Emphasized is the considerable freedom in the cut-off function which eventually can modify the Coulomb potential of two charges at sufficiently small distances. The approach provides new physical insight into nature of gauge theory and the potential energy of QCD and QED near the origin. The so obtained formalism is applied to physical mesons with a different flavor of quark and anti-quark. The excitation spectrum of the $\rho$-meson with its excellent agreement between theory and experiment is discussed as a pedagogical example.Comment: LaTeX2e, 8 pages, 5 figures, 0 tables, 29 references. Invited talk presented at the 4th International Conference on Perspectives in Hadronic Physics, at the ICTP Trieste, 12 to 16 May, 200

지역건설산업 실태와 활성화 방안 연구(Current situation and activating scheme of regional construction industry)

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Transport of a quantum degenerate heteronuclear Bose-Fermi mixture in a harmonic trap

We report on the transport of mixed quantum degenerate gases of bosonic 87Rb and fermionic 40K in a harmonic potential provided by a modified QUIC trap. The samples are transported over a distance of 6 mm to the geometric center of the anti-Helmholtz coils of the QUIC trap. This transport mechanism was implemented by a small modification of the QUIC trap and is free of losses and heating. It allows all experiments using QUIC traps to use the highly homogeneous magnetic fields that can be created in the center of a QUIC trap and improves the optical access to the atoms, e.g., for experiments with optical lattices. This mechanism may be cascaded to cover even larger distances for applications with quantum degenerate samples.Comment: 7 pages, 8 figure

Bright solitons and soliton trains in a fermion-fermion mixture

We use a time-dependent dynamical mean-field-hydrodynamic model to predict and study bright solitons in a degenerate fermion-fermion mixture in a quasi-one-dimensional cigar-shaped geometry using variational and numerical methods. Due to a strong Pauli-blocking repulsion among identical spin-polarized fermions at short distances there cannot be bright solitons for repulsive interspecies fermion-fermion interactions. However, stable bright solitons can be formed for a sufficiently attractive interspecies interaction. We perform a numerical stability analysis of these solitons and also demonstrate the formation of soliton trains. These fermionic solitons can be formed and studied in laboratory with present technology.Comment: 5 pages, 7 figure

Effect of the lattice alignment on Bloch oscillations of a Bose-Einstein condensate in a square optical lattice

We consider a Bose-Einstein condensate of ultracold atoms loaded into a square optical lattice and subject to a static force. For vanishing atom-atom interactions the atoms perform periodic Bloch oscillations for arbitrary direction of the force. We study the stability of these oscillations for non-vanishing interactions, which is shown to depend on an alignment of the force vector with respect to the lattice crystallographic axes. If the force is aligned along any of the axes, the mean field approach can be used to identify the stability conditions. On the contrary, for a misaligned force one has to employ the microscopic approach, which predicts periodic modulation of Bloch oscillations in the limit of a large forcing.Comment: 4 pages, 3 figure

Coupled atomic-molecular condensates in a double-well potential: decaying molecular oscillations

We present a four-mode model that describes coherent photo-association (PA) in a double-well Bose-Einstein condensate, focusing on the $average$ molecular populations in certain parameters. Our numerical results predict an interesting strong-damping effect of molecular oscillations by controlling the particle tunnellings and PA light strength, which may provide a promising way for creating a stable molecular condensate via coherent PA in a magnetic double-well potential.Comment: 6 pages, 4 figures, submitte

Monte-Carlo generator for e+e- annihilation into lepton and hadron pairs with precise radiative corrections

Recently, various cross sections of e+e- annihilation into hadrons were accurately measured in the energy range from 0.37 to 1.39 GeV with the CMD-2 detector at the VEPP-2M collider. In the pi+pi- channel a systematic uncertainty of 0.6% has been achieved. A Monte-Carlo Generator Photon Jets (MCGPJ) was developed to simulate events of the Bhabha scattering as well as production of two charged pions, kaons and muons. Based on the formalism of Structure Functions, the leading logarithmic contributions related to the emission of photon jets in the collinear region are incorporated into the MC generator. Radiative corrections (RC) in the first order of alpha are accounted for exactly. The theoretical precision of the cross sections with RC is estimated to be better than 0.2%. Numerous tests of the program as well as comparison with other MC generators and CMD-2 experimental data are presented.Comment: LaTeX, 23 pages with 18 figure

A Covariant Path Amplitude Description of Flavour Oscillations: The Gribov-Pontecorvo Phase for Neutrino Vacuum Propagation is Right

An extended study is performed of geometrical and kinematical assumptions used in calculations of the neutrino oscillation phase. The almost universally employed `equal velocity' assumption, in which all neutrino mass eigenstates are produced at the same time, is shown to underestimate, by a factor of two, the neutrino propagation contribution to the phase. Taking properly into account, in a covariant path amplitude calculation, the incoherent nature of neutrino production as predicted by the Standard Model, results in an important source propagator contribution to the phase. It is argued that the commonly discussed Gaussian `wave packets' have no basis within quantum mechanics and are the result of a confused amalgam of quantum and classical wave concepts.Comment: 39 pages, 1 table, 1 figure. Subject matter similar to hep-ph/0110064, hep-ph/0110066. More pedagogical presentation addressing referee criticism of earlier paper