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

Rocío 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