14,804 research outputs found
Chromospheric Dynamics and Line Formation
The solar chromosphere is very dynamic, due to the presence of large
amplitude hydrodynamic waves. Their propagation is affected by NLTE radiative
transport in strong spectral lines, which can in turn be used to diagnose the
dynamics of the chromosphere. We give a basic introduction into the equations
of NLTE radiation hydrodynamics and describe how they are solved in current
numerical simulations. The comparison with observation shows that
one-dimensional codes can describe strong brightenings quite well, but the
overall chromospheric dynamics appears to be governed by three-dimensional
shock propagation.Comment: Lecture notes and review, held at Kodaikanal Winter School on Solar
Physics, Dec 2006. This version contains corrected page numbers for some of
the reference
Efimov Physics around the neutron rich Calcium-60 isotope
We calculate the neutron-Calcium-60 S-wave scattering phase shifts using
state of the art coupled-cluster theory combined with modern ab initio
interactions derived from chiral effective theory. Effects of three-nucleon
forces are included schematically as density dependent nucleon-nucleon
interactions. This information is combined with halo effective field theory in
order to investigate the Calcium-60-neutron-neutron system. We predict
correlations between different three-body observables and the two-neutron
separation energy of Calcium-62. This provides evidence of Efimov physics along
the Calcium isotope chain. Experimental key observables that facilitate a test
of our findings are discussed.Comment: 5 pages, 4 figure
Pauli blocking effects and Cooper triples in three-component Fermi gases
We investigate the effect of Pauli blocking on universal two- and three-body
states in the medium. Their corresponding energies are extracted from the poles
of two- and three-body in-medium scattering amplitudes. Compared to the vacuum,
the binding of dimer and trimer states is reduced by the medium effects. In
two-body scattering, the well-known physics of Cooper pairs is recovered. In
the three-body sector, we find a new class of positive energy poles which can
be interpreted as Cooper triples.Comment: 19 pages, 9 figures, discussion expanded, final versio
Orthogonality relations for triple modes at dielectric boundary surfaces
We work out the orthogonality relations for the set of Carniglia-Mandel
triple modes which provide a set of normal modes for the source-free
electromagnetic field in a background consisting of a passive dielectric
half-space and the vacuum, respectively. Due to the inherent computational
complexity of the problem, an efficient strategy to accomplish this task is
desirable, which is presented in the paper. Furthermore, we provide all main
steps for the various proofs pertaining to different combinations of triple
modes in the orthogonality integral.Comment: 15 page
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