637 research outputs found
Matter-wave solitons supported by dissipation
We show how novel types of long-lived self-localized matter waves can be
constructed with Bose-Einstein condensates. The ingredients leading to such
structures are a spatial phase generating a flux of atoms towards the
condensate center and the dissipative mechanism provided by the inelastic
three-body collisions in atomic Bose-Einstein condensates. The outcome is an
striking example of nonlinear structure supported by dissipation
A Brief Report on a Major International Sociological Conference
This paper offers a brief presentation of the resettlement conference entitled "Economics, Social Justice, and Ethics in Development-Caused Involuntary Migration" that took place in the Hague from October 4th to 8th, 2010, as part of the broader 15th Metropolis Conference. The focus of the paper is on the contents of this high-level scientific event as well as on the broader concerns animating the community of resettlement researchers, namely the problems of economics, ethics and social justice in involuntary resettlement processes. In this context, the trailblazing contributions of Professor Michael Cernea as well as his enthusiasm and constant encouragement for young researchers are singled out for special attention
Numerical Object Oriented Quantum Field Theory Calculations
The qft++ package is a library of C++ classes that facilitate numerical (not
algebraic) quantum field theory calculations. Mathematical objects such as
matrices, tensors, Dirac spinors, polarization and orbital angular momentum
tensors, etc. are represented as C++ objects in qft++. The package permits
construction of code which closely resembles quantum field theory expressions,
allowing for quick and reliable calculations.Comment: 9 pages, 3 figures, submitted to Comp. Phys. Com
The SGR 1806-20 magnetar signature on the Earth's magnetic field
SGRs denote ``soft -ray repeaters'', a small class of slowly spinning
neutron stars with strong magnetic fields. On 27 December 2004, a giant flare
was detected from magnetar SGR 1806-20. The initial spike was followed by a
hard-X-ray tail persisting for 380 s with a modulation period of 7.56 s. This
event has received considerable attention, particularly in the astrophysics
area. Its relevance to the geophysics community lies in the importance of
investigating the effects of such an event on the near-earth electromagnetic
environment. However, the signature of a magnetar flare on the geomagnetic
field has not previously been investigated. Here, by applying wavelet analysis
to the high-resolution magnetic data provided by the CHAMP satellite, a
modulated signal with a period of 7.5 s over the duration of the giant flare
appears in the observed data. Moreover, this event was detected by the
energetic ion counters onboard the DEMETER satellite.Comment: Science Editors' Choice:
http://www.sciencemag.org/content/vol314/issue5798/twil.dt
s-ordered phase-sum and phase-difference distribuitons of entangled coherent states
The -ordered phase-sum and phase-difference distributions are considered
for Bell-like superpositions of two-mode coherent states. The distributions are
sensitive, respectively, to the sum and difference of the phases of the
entangled coherent states. They show loss of information about the entangled
state and may take on negative values for some orderings .Comment: 8 pages, 2 figures, iopart. accepted for publication in J. Opt. B:
Quantum Semiclass Op
Stabilization of high-order solutions of the cubic Nonlinear Schrodinger Equation
In this paper we consider the stabilization of non-fundamental unstable
stationary solutions of the cubic nonlinear Schrodinger equation. Specifically
we study the stabilization of radially symmetric solutions with nodes and
asymmetric complex stationary solutions. For the first ones we find partial
stabilization similar to that recently found for vortex solutions while for the
later ones stabilization does not seem possible
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