2,973 research outputs found
Acylsulfonamide safety-catch linker : promise and limitations for solid-phase oligosaccharide synthesis
Safety-catch linkers are useful for solid-phase oligosaccharide synthesis as they are orthogonal to many common protective groups. A new acylsulfonamide safety-catch linker was designed, synthesized and employed during glycosylations using an automated carbohydrate synthesizer. The analysis of the cleavage products revealed shortcomings for oligosaccharide synthesis
Six-body Light-Front Tamm-Dancoff approximation and wave functions for the massive Schwinger model
The spectrum of the massive Schwinger model in the strong coupling region is
obtained by using the light-front Tamm-Dancoff (LFTD) approximation up to
including six-body states. We numerically confirm that the two-meson bound
state has a negligibly small six-body component. Emphasis is on the usefulness
of the information about states (wave functions). It is used for identifying
the three-meson bound state among the states below the three-meson threshold.
We also show that the two-meson bound state is well described by the wave
function of the relative motion.Comment: 19 pages, RevTeX, 7 figures are available upon request; Minor errors
have been corrected; Final version to appear in Phys.Rev.
Finite-size effects on a lattice calculation
We study in this paper the finite-size effects of a non-periodic lattice on a
lattice calculation. To this end we use a finite lattice equipped with a
central difference derivative with homogeneous boundary conditions to calculate
the bosonic mass associated to the Schwinger model. We found that the
homogeneous boundary conditions produce absence of fermion doubling and chiral
invariance, but we also found that in the continuum limit this lattice model
does not yield the correct value of the boson mass as other models do. We
discuss the reasons for this and, as a result, the matrix which cause the
fermion doubling problem is identified.Comment: 8 pages, no figures, extended version, five references adde
ERTS-1 applications to Minnesota land use mapping
Land use class definitions that can be operationally employed with ERTS-1 imagery are being developed with the cooperation of personnel from several state, regional, and federal agencies with land management responsibilities within the state and the University of Minnesota. Investigations of urban, extractive, forest, and wetlands areas indicate that it is feasible to subdivide each of these classes into several sub-classes with the use of ERTS-1 images from one or more time periods
Sonoluminescing air bubbles rectify argon
The dynamics of single bubble sonoluminescence (SBSL) strongly depends on the
percentage of inert gas within the bubble. We propose a theory for this
dependence, based on a combination of principles from sonochemistry and
hydrodynamic stability. The nitrogen and oxygen dissociation and subsequent
reaction to water soluble gases implies that strongly forced air bubbles
eventually consist of pure argon. Thus it is the partial argon (or any other
inert gas) pressure which is relevant for stability. The theory provides
quantitative explanations for many aspects of SBSL.Comment: 4 page
Dynamics of the Light-Cone Zero Modes: Theta Vacuum of the Massive Schwinger Model
The massive Schwinger model is quantized on the light cone with great care on
the bosonic zero modes by putting the system in a finite (light-cone) spatial
box. The zero mode of survives Dirac's procedure for the constrained
system as a dynamical degree of freedom. After regularization and quantization,
we show that the physical space condition is consistently imposed and relates
the fermion Fock states to the zero mode of the gauge field. The vacuum is
obtained by solving a Schr\"odinger equation in a periodic potential, so that
the theta is understood as the Bloch momentum. We also construct a one-meson
state in the fermion-antifermion sector and obtained the Schr\"odinger equation
for it.Comment: 23 pages, RevTex, no figure
A Density Matrix Renormalization Group Approach to an Asymptotically Free Model with Bound States
We apply the DMRG method to the 2 dimensional delta function potential which
is a simple quantum mechanical model with asymptotic freedom and formation of
bound states. The system block and the environment block of the DMRG contain
the low energy and high energy degrees of freedom, respectively. The ground
state energy and the lowest excited states are obtained with very high
accuracy. We compare the DMRG method with the Similarity RG method and propose
its generalization to field theoretical models in high energy physics.Comment: REVTEX file, 4 pages, 1 Table, 3 eps Figures. Explanation on the
extension to many-body QFT problems added, 3 new references and some minor
changes. New forma
Towards Solving QCD in Light-Cone Quantization -- On the Spectrum of the Transverse Zero Modes for SU(2)
The formalism for a non-abelian pure gauge theory in (2+1) dimensions has
recently been derived within Discretized Light-Cone Quantization, restricting
to the lowest {\it transverse} momentum gluons. It is argued why this model can
be a paradigm for full QCD. The physical vacuum becomes non-trivial even in
light-cone quantization. The approach is brought here to tractable form by
suppressing by hand both the dynamical gauge and the constraint zero mode, and
by performing a Tamm-Dancoff type Fock-space truncation. Within that model the
Hamiltonian is diagonalized numerically, yielding mass spectra and
wavefunctions of the glue-ball states. We find that only color singlets have a
stable and discrete bound state spectrum. The connection with confinement is
discussed. The structure function of the gluons has a shape like . The existence of the continuum limit is verified by deriving a
coupled set of integral equations.Comment: 1 Latex file & 9 Postscript files; tarred, compressed and uuencode
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