3,323 research outputs found
Book Review: Euroscepticism within the EU institutions: diverging views of europe
Since its origins, there have been competing views concerning the nature, scope and objectives of the process of integration and of the European Union. Attitudes towards Europe and European integration, both among political elites and citizens, have been much studied over the last 15 years. But there is no comprehensive analysis of these competing views of Europe at the supranational level. Stuart A. Brown reviews Nathalie Brack and Olivier Costa’s edited collection on the divergence in views about the European Union, which lends insight into its consequences for the functioning of the EU and its institutions
Entanglement in the classical limit: quantum correlations from classical probabilities
We investigate entanglement for a composite closed system endowed with a
scaling property allowing to keep the dynamics invariant while the effective
Planck constant hbar_eff of the system is varied. Entanglement increases as
hbar_eff goes to 0. Moreover for sufficiently low hbar_eff the evolution of the
quantum correlations, encapsulated for example in the quantum discord, can be
obtained from the mutual information of the corresponding \emph{classical}
system. We show this behavior is due to the local suppression of path
interferences in the interaction that generates the entanglement. This behavior
should be generic for quantum systems in the classical limit.Comment: 10 pages 3 figure
Closed orbits and spatial density oscillations in the circular billiard
We present a case study for the semiclassical calculation of the oscillations
in the particle and kinetic-energy densities for the two-dimensional circular
billiard. For this system, we can give a complete classification of all closed
periodic and non-periodic orbits. We discuss their bifurcations under variation
of the starting point r and derive analytical expressions for their properties
such as actions, stability determinants, momentum mismatches and Morse indices.
We present semiclassical calculations of the spatial density oscillations using
a recently developed closed-orbit theory [Roccia J and Brack M 2008 Phys. Rev.
Lett. 100 200408], employing standard uniform approximations from perturbation
and bifurcation theory, and test the convergence of the closed-orbit sum.Comment: LaTeX, 42 pp., 17 figures (24 *.eps files, 1 *.tex file); final
version (v3) to be published in J. Phys.
Periodic-orbit approach to the nuclear shell structures with power-law potential models: Bridge orbits and prolate-oblate asymmetry
Deformed shell structures in nuclear mean-field potentials are systematically
investigated as functions of deformation and surface diffuseness. As the
mean-field model to investigate nuclear shell structures in a wide range of
mass numbers, we propose the radial power-law potential model, V \propto
r^\alpha, which enables a simple semiclassical analysis by the use of its
scaling property. We find that remarkable shell structures emerge at certain
combinations of deformation and diffuseness parameters, and they are closely
related to the periodic-orbit bifurcations. In particular, significant roles of
the "bridge orbit bifurcations" for normal and superdeformed shell structures
are pointed out. It is shown that the prolate-oblate asymmetry in deformed
shell structures is clearly understood from the contribution of the bridge
orbit to the semiclassical level density. The roles of bridge orbit
bifurcations in the emergence of superdeformed shell structures are also
discussed.Comment: 20 pages, 23 figures, revtex4-1, to appear in Phys. Rev.
Curvature Correction in the Strutinsky's Method
Mass calculations carried out by Strutinsky's shell correction method are
based on the notion of smooth single particle level density. The smoothing
procedure is always performed using curvature correction. In the presence of
curvature correction a smooth function remains unchanged if smoothing is
applied. Two new curvature correction methods are introduced. The performance
of the standard and new methods are investigated using harmonic oscillator and
realistic potentials.Comment: 4 figures, submitted to Journal of Physics G: Nuclear and Particle
Physic
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