2,249 research outputs found
Systemic risk analysis using forward-looking distance-to-default series
Based on contingent claims theory, this paper develops a method to monitor systemic risk in the European banking system. Aggregated Distance-to-Default series are generated using option prices information from systemically important banks and the DJ STOXX Banks Index. These indicators provide methodological advantages in monitoring vulnerabilities in the banking system over time: 1) they capture interdependences and joint risk of distress in systemically important banks; 2) their forward-looking feature endow them with early signaling properties compared to traditional approaches in the literature and other market-based indicators; and 3) they produce simultaneously both smooth and informative long-term signals and quick and clear reaction to market distress.Systemic risk ; Banks and banking - Europe
Purcell factor of Mie resonators featuring electric and magnetic modes
We present a modal approach to compute the Purcell factor in Mie resonators
exhibiting both electric and magnetic resonances. The analytic expressions of
the normal modes are used to calculate the effective volumes. We show that
important features of the effective volume can be predicted thanks to the
translation-addition coefficients of a displaced dipole. Using our formalism,
it is easy to see that, in general, the Purcell factor of Mie resonators is not
dominated by a single mode, but rather by a large superposition. Finally we
consider a silicon resonator homogeneously doped with electric dipolar
emitters, and we show that the average electric Purcell factor dominates over
the magnetic one
Using a graphical programming language to write CAMAC/GPIB instrument drivers
To reduce the complexities of conventional programming, graphical software was used in the development of instrumentation drivers. The graphical software provides a standard set of tools (graphical subroutines) which are sufficient to program the most sophisticated CAMAC/GPIB drivers. These tools were used and instrumentation drivers were successfully developed for operating CAMAC/GPIB hardware from two different manufacturers: LeCroy and DSP. The use of these tools is presented for programming a LeCroy A/D Waveform Analyzer
The role of the angular momentum of light in Mie scattering. Excitation of dielectric spheres with Laguerre-Gaussian modes
We present a method to enhance the ripple structure of the scattered
electromagnetic field in the visible range through the use of Laguerre-Gaussian
beams. The position of these enhanced ripples as well as their linewidths can
be controlled using different optical beams and sizes of the spheres.Comment: 10 pages, 4 figures, 1 table,
http://dx.doi.org/10.1016/j.jqsrt.2012.10.01
Angular momentum-induced circular dichroism in non-chiral nanostructures
Circular dichroism (CD), i.e. the differential response of a system to left
and right circularly polarized light, is one of the only techniques capable of
providing morphological information of certain samples. In biology, for
instance, CD spectroscopy is widely used to study the structure of proteins.
More recently, it has also been used to characterize metamaterials and
plasmonic structures. Typically, CD can only be observed in chiral objects.
Here, we present experimental results showing that a non-chiral sample such as
a sub-wavelength circular nano-aperture can produce giant CD when a vortex beam
is used to excite it. These measurements can be understood by studying the
symmetries of the sample and the total angular momentum that vortex beams
carry. Our results show that CD can provide a wealth of information about the
sample when combined with the control of the total angular momentum of the
input field
On the transformations generated by the electromagnetic spin and orbital angular momentum operators
We present a study of the properties of the transversal "spin angular
momentum" and "orbital angular momentum" operators. We show that the "spin
angular momentum" operators are generators of spatial translations which depend
on helicity and frequency and that the "orbital angular momentum" operators
generate transformations which are a sequence of this kind of translations and
rotations. We give some examples of the use of these operators in light matter
interaction problems. Their relationship with the helicity operator allows to
involve the electromagnetic duality symmetry in the analysis. We also find that
simultaneous eigenstates of the three "spin" operators and parity define a type
of standing modes which has been recently singled out for the interaction of
light with chiral molecules. With respect to the relationship between "spin
angular momentum", polarization, and total angular momentum, we show that,
except for the case of a single plane wave, the total angular momentum of the
field is decoupled from its vectorial degrees of freedom even in the regime
where the paraxial approximation holds. Finally, we point out a relationship
between the three "spin" operators and the spatial part of the Pauli-Lubanski
four vector
Colonial Debts
RocÃo Zambrana uses the current political-economic moment in Puerto Rico to outline how debt functions as both an apparatus that strengthens neoliberalism and the island's colonial relation to the United States
Transverse multipolar light-matter couplings in evanescent waves
We present an approach to study the interaction between matter and evanescent
fields. The approach is based on the decomposition of evanescent plane waves
into multipoles of well-defined angular momentum transverse to both decay and
propagation directions. We use the approach to identify the origin of the
recently observed directional coupling of emitters into guided modes, and of
the opposite Zeeman state excitation of atoms near a fiber. We explain how to
rigorously quantify both effects, and show that the directionality and the
difference in excitation rates grow exponentially with the multipolar order of
the light-matter interaction. We also use the approach to study and maximize
the transverse torque exerted by an evanescent plane wave onto a given
spherical absorbing particle. The maximum occurs at the quadrupolar order of
the particle, and for a particular polarization of the plane wave. All the
obtained physical insights can be traced back to the two main features of the
decomposition of evanescent plane waves into transverse multipolar modes: A
polarization independent exponential dominance of modes with large transverse
angular momentum, and a polarization controlled parity selection rule.Comment: Last version with slight changes in the figures and tex
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