515 research outputs found
Shape coexistence in neutron-deficient Kr isotopes: Constraints on the single-particle spectrum of self-consistent mean-field models from collective excitations
We discuss shape coexistence in the neutron-deficient Kr72-Kr78 isotopes in
the framework of configuration mixing calculations of particle-number and
angular-momentum projected axial mean-field states obtained from
self-consistent calculations with the Skyrme interaction SLy6 and a
density-dependent pairing interaction. While our calculation reproduces
qualitatively and quantitatively many of the global features of these nuclei,
such as coexistence of prolate and oblate shapes, their strong mixing at low
angular momentum, and the deformation of collective bands, the ordering of our
calculated low-lying levels is at variance with experiment. We analyse the role
of the single-particle spectrum of the underlying mean-field for the spectrum
of collective excitations.Comment: accepted for publication in Phys. Rev.
Is there a Jordan geometry underlying quantum physics?
There have been several propositions for a geometric and essentially
non-linear formulation of quantum mechanics. From a purely mathematical point
of view, the point of view of Jordan algebra theory might give new strength to
such approaches: there is a ``Jordan geometry'' belonging to the Jordan part of
the algebra of observables, in the same way as Lie groups belong to the Lie
part. Both the Lie geometry and the Jordan geometry are well-adapted to
describe certain features of quantum theory. We concentrate here on the
mathematical description of the Jordan geometry and raise some questions
concerning possible relations with foundational issues of quantum theory.Comment: 30 page
Renormalization Group Theory for a Perturbed KdV Equation
We show that renormalization group(RG) theory can be used to give an analytic
description of the evolution of a perturbed KdV equation. The equations
describing the deformation of its shape as the effect of perturbation are RG
equations. The RG approach may be simpler than inverse scattering theory(IST)
and another approaches, because it dose not rely on any knowledge of IST and it
is very concise and easy to understand. To the best of our knowledge, this is
the first time that RG has been used in this way for the perturbed soliton
dynamics.Comment: 4 pages, no figure, revte
Base manifolds for fibrations of projective irreducible symplectic manifolds
Given a projective irreducible symplectic manifold of dimension , a
projective manifold and a surjective holomorphic map with
connected fibers of positive dimension, we prove that is biholomorphic to
the projective space of dimension . The proof is obtained by exploiting two
geometric structures at general points of : the affine structure arising
from the action variables of the Lagrangian fibration and the structure
defined by the variety of minimal rational tangents on the Fano manifold
Binary Nonlinearization of Lax pairs of Kaup-Newell Soliton Hierarchy
Kaup-Newell soliton hierarchy is derived from a kind of Lax pairs different
from the original ones. Binary nonlinearization procedure corresponding to the
Bargmann symmetry constraint is carried out for those Lax pairs. The proposed
Lax pairs together with adjoint Lax pairs are constrained as a hierarchy of
commutative, finite dimensional integrable Hamiltonian systems in the Liouville
sense, which also provides us with new examples of finite dimensional
integrable Hamiltonian systems. A sort of involutive solutions to the
Kaup-Newell hierarchy are exhibited through the obtained finite dimensional
integrable systems and the general involutive system engendered by binary
nonlinearization is reduced to a specific involutive system generated by
mono-nonlinearization.Comment: 15 pages, plain+ams tex, to be published in Il Nuovo Cimento
Helical vs. fundamental solitons in optical fibers
We consider solitons in a nonlinear optical fiber with a single polarization
in a region of parameters where it carries exactly two distinct modes, the
fundamental one and the first-order helical mode. From the viewpoint of
applications to dense-WDM communication systems, this opens way to double the
number of channels carried by the fiber. Aside from that, experimental
observation of helical (spinning) solitons and collisions between them and with
fundamental solitons are issues of fundamental interest. We introduce a system
of coupled nonlinear Schroedinger equations for fundamental and helical modes,
which have nonstandard values of the cross-phase-modulation coupling constants,
and investigate, analytically and numerically, results of "complete" and
"incomplete" collisions between solitons carried by the two modes. We conclude
that the collision-induced crosstalk is partly attenuated in comparison with
the usual WDM system, which sometimes may be crucially important, preventing
merger of the colliding solitons into a breather. The interaction between the
two modes is found to be additionally strongly suppressed in comparison with
that in the WDM system in the case when a dispersion-shifted or
dispersion-compensated fiber is used.Comment: a plain latex file with the text and two ps files with figures.
Physica Scripta, in pres
-kinks in strongly ac driven sine-Gordon systems
We demonstrate that -kinks exist in non-parametrically ac driven
sine-Gordon systems if the ac drive is sufficiently fast. It is found that, at
a critical value of the drive amplitude, there are two stable and two unstable
equilibria in the sine-Gordon phase. The pairwise symmetry of these equilibria
implies the existence of a one-parameter family of -kink solutions in the
reduced system. In the dissipative case of the ac driven sine-Gordon systems,
corresponding to Josephson junctions, the velocity is selected by the balance
between the perturbations. The results are derived from a perturbation analysis
and verified by direct numerical simulations.Comment: 4 pages, 2 figures, revte
Numerical evidence for `multi-scalar stars'
We present a class of general relativistic soliton-like solutions composed of
multiple minimally coupled, massive, real scalar fields which interact only
through the gravitational field. We describe a two-parameter family of
solutions we call ``phase-shifted boson stars'' (parameterized by central
density rho_0 and phase delta), which are obtained by solving the ordinary
differential equations associated with boson stars and then altering the phase
between the real and imaginary parts of the field. These solutions are similar
to boson stars as well as the oscillating soliton stars found by Seidel and
Suen [E. Seidel and W.M. Suen, Phys. Rev. Lett. 66, 1659 (1991)]; in
particular, long-time numerical evolutions suggest that phase-shifted boson
stars are stable. Our results indicate that scalar soliton-like solutions are
perhaps more generic than has been previously thought.Comment: Revtex. 4 pages with 4 figures. Submitted to Phys. Rev.
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