Expected budget deficits and interest rate swap spreads - Evidence for France, Germany and Italy

This study analyses whether expected budget deficits have an impact on interest rate swap spreads in France, Germany and Italy. We use monthly deficit forecasts from financial market participants to take the forward-looking behaviour of financial markets into account. Results of a SUR estimation show no significant impact of expected deficits on swap spreads over the whole sample period (1994-2004). However, we find an increase in market discipline for Germany and France since the signing of the Stability and Growth Pact, and for Germany also since the start of European monetary union. --Budget deficits,interest rate swap spreads,EMU,Stability and Growth Pact

Dielectric response effects in attosecond time-resolved streaked photoelectron spectra of metal surfaces

The release of conduction-band electrons from a metal surface by a sub-femtosecond extreme ultraviolet (XUV) pulse, and their propagation through the solid, provokes a dielectric response in the solid that acts back on the photoelectron wave packet. We calculated the (wake) potential associated with this photoelectron self-interaction in terms of bulk and surface plasmon excitations and show that it induces a considerable, XUV-frequency-dependent temporal shift in laser-streaked XUV photoemission spectra, suggesting the observation of the ultrafast solid-state dielectric response in contemporary streaked photoemission experiments.Comment: 4 pages and 4 figures, submitted to PR

Echo of the Quantum Phase Transition of CeCu6−x_{6-x}Aux_x in XPS: Breakdown of Kondo Screening

We present an X-ray photoemission study of the heavy-fermion system CeCu$_{6-x}$Au$_x$ across the magnetic quantum phase transition of this compound at temperatures above the single-ion Kondo temperature $T_K$. In dependence of the Au concentration $x$ we observe a sudden change of the $f$-occupation number $n_f$ and the core-hole potential $U_{df}$ at the critical concentration $x_c=0.1$. We interpret these findings in the framework of the single-impurity Anderson model. Our results are in excellent agreement with findings from earlier UPS measurements %\cite{klein08qpt} and provide further information about the precursors of quantum criticality at elevated temperatures.Comment: 5 pages, 3 figures; published version, references updated, minor changes in wordin

Band Mapping in One-Step Photoemission Theory: Multi-Bloch-Wave Structure of Final States and Interference Effects

A novel Bloch-waves based one-step theory of photoemission is developed within the augmented plane wave formalism. Implications of multi-Bloch-wave structure of photoelectron final states for band mapping are established. Interference between Bloch components of initial and final states leads to prominent spectral features with characteristic frequency dispersion experimentally observed in VSe_2 and TiTe_2. Interference effects together with a non-free-electron nature of final states strongly limit the applicability of the common direct transitions band mapping approach, making the tool of one-step analysis indispensable.Comment: 4 jpg figure

Superpenetration of a high energy Q barQ bound state through random color fields

The transmission amplitude of a color dipole through a random external color field is computed in the eikonal approximation in order to study the absorption of high energy quarkonium by nuclear target. It is shown that the internal color state of the dipole becomes randomized and all possible color states are eventually equi-partitioned, while the probability of finding a color singlet bound state attenuates not exponentially, but inversely proportional to the distance L of the random field zone which the dipole has traveled.Comment: 7 pages (3 figures

Madelung potentials and covalency effect in strained La1−x_{1-x}Srx_xMnO3_3 thin films studied by core-level photoemission spectroscopy

We have investigated the shifts of the core-level photoemission spectra of La$_{0.6}$Sr$_{0.4}$MnO$_3$ thin films grown on three kinds of substrates, SrTiO$_3$, (LaAlO$_3$)$_{0.3}$-(SrAl$_{0.5}$Ta$_{0.5}$O$_3$)$_{0.7}$, and LaAlO$_3$. The experimental shifts of the La 4d and Sr 3d core levels are almost the same as the calculation, which we attribute to the absence of covalency effects on the Madelung potentials at these atomic sites due to the nearly ionic character of these atoms. On the other hand, the experimental shifts of the O $1s$ and Mn $2p$ core levels are negligibly small, in disagreement with the calculation. We consider that this is due to the strong covalent character of the Mn-O bonds.Comment: 4 pages, 5 figure

Scanning the Quark-Gluon Plasma with Charmonium

We suggest the variation of charmonium suppression with Feynman x_F in heavy ion collisions as a novel and sensitive probe for the properties of the matter created in such reactions. In contrast to the proton-nucleus case where nuclear suppression is weakest at small x_F, final state interactions with the comoving matter create a minimum at x_F=0, which is especially deep and narrow if a quark-gluon plasma is formed. While a particularly strong effect is predicted at SPS, at the higher RHIC energy it overlaps with the expected sharp variation with x_F of nuclear effects and needs comparison with proton-nucleus data. If thermal enhancement of J/\Psi production takes over at the energies of RHIC and LHC, it will form an easily identified peak, rather than dip in x_F dependence. We predict a steep dependence on centrality and suggest that this new probe is complementary to the dependence on transverse energy, and is more sensitive to a scenario of final state interactions.Comment: 5 pages including 3 figures. Stylistic and clarifying corrections are mad

Chemical potential shift induced by double-exchange and polaronic effects in Nd_{1-x}Sr_xMnO_3

We have studied the chemical potential shift as a function of temperature in Nd$_{1-x}$Sr$_x$MnO$_3$ (NSMO) by measurements of core-level photoemission spectra. For ferromagnetic samples ($x=0.4$ and 0.45), we observed an unusually large upward chemical potential shift with decreasing temperature in the low-temperature region of the ferromagnetic metallic (FM) phase. This can be explained by the double-exchange (DE) mechanism if the $e_g$ band is split by dynamical/local Jahn-Teller effect. The shift was suppressed near the Curie temperature ($T_C$), which we attribute to the crossover from the DE to lattice-polaron regimes.Comment: 5 pages, 6 figure

Renormalization of f-levels away from the Fermi energy in electron excitation spectroscopies: Density functional results of Nd2−x_{2-x}Cex_xCuO4_4

Relaxation energies for photoemission, when an occupied electronic state is excited, and for inverse photoemission, when an empty state is filled, are calculated within the density functional theory with application to Nd$_{2-x}$Ce$_x$CuO$_4$. The associated relaxation energies are obtained by computing differences in total energies between the ground state and an excited state in which one hole or electron is added into the system. The relaxation energies of f-electrons are found to be of the order of several eV's, indicating that f-bands will appear substantially away from the Fermi energy ($E_F$) in their spectroscopic images, even if these bands lie near $E_F$. Our analysis explains why it would be difficult to observe f electrons at the $E_F$ even in the absence of strong electronic correlations.Comment: 6 pages, 1 figure, 1 tabl

Elastic Scattering Susceptibility of the High Temperature Superconductor Bi2Sr2CaCu2O8+x: A Comparison between Real and Momentum Space Photoemission Spectroscopies

The joint density of states (JDOS) of Bi2Sr2CaCu2O8+x is calculated by evaluating the autocorrelation of the single particle spectral function A(k,omega) measured from angle resolved photoemission spectroscopy (ARPES). These results are compared with Fourier transformed (FT) conductance modulations measured by scanning tunneling microscopy (STM). Good agreement between the two experimental probes is found for two different doping values examined. In addition, by comparing the FT-STM results to the autocorrelated ARPES spectra with different photon polarization, new insight on the form of the STM matrix elements is obtained. This shines new light on unsolved mysteries in the tunneling data.Comment: Revised now available at: Phys. Rev. Lett. 96, 067005 (2006