1,025 research outputs found
Low Energy States in the SU(N) Skyrme Models
We show that any solution of the SU(2) Skyrme model can be used to give a
topologically trivial solution of the SU(4) one. In addition, we extend the
method introduced by Houghton et al. and use harmonic maps from S2 to CP(N-1)
to construct low energy configurations of the SU(N) Skyrme models. We show that
one of such maps gives an exact, topologically trivial, solution of the SU(3)
model. We study various properties of these maps and show that, in general,
their energies are only marginally higher than the energies of the
corresponding SU(2) embeddings. Moreover, we show that the baryon (and energy)
densities of the SU(3) configurations with baryon number B=2-4 are more
symmetrical than their SU(2) analogues. We also present the baryon densities
for the B=5 and B=6 configurations and discuss their symmetries.Comment: latex : 25 pages, 9 Postscript figures, uses eps
Two component Bose-Hubbard model with higher angular momentum states
We study a Bose-Hubbard Hamiltonian of ultracold two component gas of spinor
Chromium atoms. Dipolar interactions of magnetic moments while tuned resonantly
by ultralow magnetic field can lead to spin flipping. Due to approximate axial
symmetry of individual lattice site, total angular momentum is conserved.
Therefore, all changes of the spin are accompanied by the appearance of the
angular orbital momentum. This way excited Wannier states with non vanishing
angular orbital momentum can be created. Resonant dipolar coupling of the two
component Bose gas introduces additional degree of control of the system, and
leads to a variety of different stable phases. The phase diagram for small
number of particles is discussed.Comment: 4 pages, 2 figure
SU(5) Gravitating Monopoles
Spherically symmetric solutions of the SU(5) Einstein-Yang-Mills-Higgs system
are constructed using the harmonic map ansatz \cite{IS}. This way the problem
reduces to solving a set of ordinary differential equations for the appropriate
profile functions.Comment: 12 pages, 3 Figure
Interaction and Localization of One-electron Orbitals in an Organic Molecule: Fictitious Parameter Analysis for Multi-physics Simulations
We present a new methodology to analyze complicated multi-physics simulations
by introducing a fictitious parameter. Using the method, we study quantum
mechanical aspects of an organic molecule in water. The simulation is
variationally constructed from the ab initio molecular orbital method and the
classical statistical mechanics with the fictitious parameter representing the
coupling strength between solute and solvent. We obtain a number of
one-electron orbital energies of the solute molecule derived from the
Hartree-Fock approximation, and eigenvalue-statistical analysis developed in
the study of nonintegrable systems is applied to them. Based on the results, we
analyze localization properties of the electronic wavefunctions under the
influence of the solvent.Comment: 4 pages, 5 figures, the revised version will appear in J. Phys. Soc.
Jpn. Vol.76 (No.1
Nonuniversality in level dynamics
Statistical properties of parametric motion in ensembles of Hermitian banded
random matrices are studied. We analyze the distribution of level velocities
and level curvatures as well as their correlation functions in the crossover
regime between three universality classes. It is shown that the statistical
properties of level dynamics are in general non-universal and strongly depend
on the way in which the parametric dynamics is introduced.Comment: 24 pages + 10 figures (not included, avaliable from the author),
submitted to Phys. Rev.
Baby Skyrme models for a class of potentials
We consider a class of (2+1) dimensional baby Skyrme models with potentials
that have more than one vacum. These potentials are generalisation of old and
new baby Skyrme models;they involve more complicated dependence on phi_3.We
find that when the potential is invariant under phi_3 -> -phi_3 the
configuration corresponding to the baby skyrmions lying "on top of each other"
are the minima of the energy. However when the potential breaks this symmetry
the lowest field configurations correspond to separated baby skyrmions. We
compute the energy distributions for skyrmions of degrees between one and eight
and discuss their geometrical shapes and binding energies. We also compare the
2-skyrmion states for these potentials. Most of our work has been performed
numerically with the model being formulated in terms of three real scalar
fields (satisfying one constraint).Comment: LaTeX, 14 pages, 10 figure
SO(3) Gauged Soliton of an O(4) Sigma Model on
Vector gauged sigma models on are presented. The
topological charge supplying the lower bound on the energy and rendering the
soliton stable coincides with the Baryon number of the Skyrmion. These solitons
have vanishing magnetic monopole flux. To exhibit the existence of such
solitons, the equations of motion of one of these models is integrated
numerically. The structure of the conserved Baryon current is briefly
discussed.Comment: 14 pages, latex, 3 figures available from the authors on reques
Topological discrete kinks
A spatially discrete version of the general kink-bearing nonlinear
Klein-Gordon model in (1+1) dimensions is constructed which preserves the
topological lower bound on kink energy. It is proved that, provided the lattice
spacing h is sufficiently small, there exist static kink solutions attaining
this lower bound centred anywhere relative to the spatial lattice. Hence there
is no Peierls-Nabarro barrier impeding the propagation of kinks in this
discrete system. An upper bound on h is derived and given a physical
interpretation in terms of the radiation of the system. The construction, which
works most naturally when the nonlinear Klein-Gordon model has a squared
polynomial interaction potential, is applied to a recently proposed continuum
model of polymer twistons. Numerical simulations are presented which
demonstrate that kink pinning is eliminated, and radiative kink deceleration
greatly reduced in comparison with the conventional discrete system. So even on
a very coarse lattice, kinks behave much as they do in the continuum. It is
argued, therefore, that the construction provides a natural means of
numerically simulating kink dynamics in nonlinear Klein-Gordon models of this
type. The construction is compared with the inverse method of Flach, Zolotaryuk
and Kladko. Using the latter method, alternative spatial discretizations of the
twiston and sine-Gordon models are obtained which are also free of the
Peierls-Nabarro barrier.Comment: 14 pages LaTeX, 7 postscript figure
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