141 research outputs found
Two--Electron Atoms in Short Intense Laser Pulses
We discuss a method of solving the time dependent Schrodinger equation for
atoms with two active electrons in a strong laser field, which we used in a
previous paper [A. Scrinzi and B. Piraux, Phys. Rev. A 56, R13 (1997)] to
calculate ionization, double excitation and harmonic generation in Helium by
short laser pulses. The method employs complex scaling and an expansion in an
explicitly correlated basis. Convergence of the calculations is documented and
error estimates are provided. The results for Helium at peak intensities up to
10^15 W/cm^2 and wave length 248 nm are accurate to at least 10 %. Similarly
accurate calculations are presented for electron detachment and double
excitation of the negative hydrogen ion.Comment: 14 pages, including figure
Spectrum of Neutral Helium in Strong Magnetic Fields
We present extensive and accurate calculations for the excited state spectrum
of spin-polarized neutral helium in a range of magnetic field strengths up to
G. Of considerable interest to models of magnetic white dwarf stellar
atmospheres, we also present results for the dipole strengths of the low lying
transitions among these states. Our methods rely on a systematically saturated
basis set approach to solving the Hartree--Fock self-consistent field
equations, combined with an ``exact'' stochastic method to estimate the
residual basis set truncation error and electron correlation effects. We also
discuss the applicability of the adiabatic approximation to strongly magnetized
multi-electron atoms.Comment: 19 pages, 7 figures, 10 table
â'Subaltern Victimsâ or âUseful Resourcesâ? Migrant Women in the Lega Nord Ideology and Politics"
Since the mid-2000s we have witnessed the emergence of a new phenomenon in several European countries: the mobilisation of issues of womenâs rights and gender equality by populist radical right parties (PRR)1 in anti-immigration campaigns. Recent contributions have illustrated some aspects and contradictions of these phenomena, for instance in relation to the PRR partiesâ embrace not only of womenâs but also gay rights (Bracke 2011). Others have described the double standard applied to migrant men and women in the context of raising hostility towards the Muslim population, not only by PRR parties, but within the mainstream more generally; whereas Muslim men have been mostly described as representing a social and cultural danger to European societies as well as being inherently misogynist, Muslim women have been portrayed prevalently as victims to be rescued (Abu-Lughod 2013). Little however has been written on the gendered ideology and strategies of these parties, particularly when it comes to addressing the issue of migrant women. This chapter aims to address these gaps in the scholarly literature by focusing on the gendered dimensions of anti-immigration ideology, policy and politics in the case of the LN. In particular, we draw on the empirical findings of two research projects to analyse the instrumental mobilisation of womenâs rights by the LN to stigmatise migrant, particularly Muslim, communities
Gender, migration and the ambiguous enterprise of professionalizing domestic service: the case of vocational training for the unemployed in France
Drawing on ethnographic data concerning migrant male domestic workers, this article examines the gendered dimensions of the process of racialization in Italy and France. First, it shows that specific racialized constructions of masculinity are mobilized by the employers as well as by training and recruitment agencies. These constructions of masculinity are related to different forms of organization of the sector in each country and to different ideologies about the integration of migrants. Second, the data presented reveal the strategies used by migrant male domestic workers to reaffirm their masculinity in a traditionally feminized sector. In doing so, this article intends to explore the connections between international migration and the gendering of occupations, with regard to the construction and management of masculinities in domestic service. Finally, by examining menâs experiences, this article aims to contribute to a more complex definition of the international division of care work
The explanation of unexpected temperature dependence of the muon catalysis in solid deuterium
It is shown that due to the smallness of the inelastic cross-section of the
-atoms scattering in the crystal lattice at sufficiently low temperatures
the -mesomolecules formation from the upper state of the hyperfine
structure starts earlier than the mesoatoms thermolization. It
explains an approximate constancy of the -mesomolecule formation rate in
solid deuterium.Comment: 6 pages, 2 jpeg-figure
The helium atom in a strong magnetic field
We investigate the electronic structure of the helium atom in a magnetic
field b etween B=0 and B=100a.u. The atom is treated as a nonrelativistic
system with two interactin g electrons and a fixed nucleus. Scaling laws are
provided connecting the fixed-nucleus Hamiltonia n to the one for the case of
finite nuclear mass. Respecting the symmetries of the electronic Ham iltonian
in the presence of a magnetic field, we represent this Hamiltonian as a matrix
with res pect to a two-particle basis composed of one-particle states of a
Gaussian basis set. The corresponding generalized eigenvalue problem is solved
numerically, providing in the present paper results for vanish ing magnetic
quantum number M=0 and even or odd z-parity, each for both singlet and triplet
spin symmetry. Total electronic energies of the ground state and the first few
excitations in each su bspace as well as their one-electron ionization energies
are presented as a function of the magnetic fie ld, and their behaviour is
discussed. Energy values for electromagnetic transitions within the M=0 sub
space are shown, and a complete table of wavelengths at all the detected
stationary points with respect to their field dependence is given, thereby
providing a basis for a comparison with observed ab sorption spectra of
magnetic white dwarfs.Comment: 21 pages, 4 Figures, acc.f.publ.in J.Phys.
Economic assessment of RFID coupled with open source technologies for wood traceability in Calabria
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Ultrashort filaments of light in weakly-ionized, optically-transparent media
Modern laser sources nowadays deliver ultrashort light pulses reaching few
cycles in duration, high energies beyond the Joule level and peak powers
exceeding several terawatt (TW). When such pulses propagate through
optically-transparent media, they first self-focus in space and grow in
intensity, until they generate a tenuous plasma by photo-ionization. For free
electron densities and beam intensities below their breakdown limits, these
pulses evolve as self-guided objects, resulting from successive equilibria
between the Kerr focusing process, the chromatic dispersion of the medium, and
the defocusing action of the electron plasma. Discovered one decade ago, this
self-channeling mechanism reveals a new physics, widely extending the frontiers
of nonlinear optics. Implications include long-distance propagation of TW beams
in the atmosphere, supercontinuum emission, pulse shortening as well as
high-order harmonic generation. This review presents the landmarks of the
10-odd-year progress in this field. Particular emphasis is laid to the
theoretical modeling of the propagation equations, whose physical ingredients
are discussed from numerical simulations. Differences between femtosecond
pulses propagating in gaseous or condensed materials are underlined. Attention
is also paid to the multifilamentation instability of broad, powerful beams,
breaking up the energy distribution into small-scale cells along the optical
path. The robustness of the resulting filaments in adverse weathers, their
large conical emission exploited for multipollutant remote sensing, nonlinear
spectroscopy, and the possibility to guide electric discharges in air are
finally addressed on the basis of experimental results.Comment: 50 pages, 38 figure
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