Influence of Disorder on the Hall Effect in Bi2_2Sr2_2CuO6+δ_{6+\delta}

The in-plane resistivity and Hall coefficient have been measured for the single-layer compound Bi$_2$Sr$_2$CuO$_{6+\delta}$ for the whole range of doping states. The deviation of the Hall coefficient, $R_H$, from a high-temperature linear behavior and the temperature dependence of the Hall angle are both only weakly dependent upon doping, contrasting with Bi$_2$Sr$_{2-x}$La$_x$CuO$_{6+\delta}$ and Bi$_2$Sr$_2$CaCuO$_{8+\delta}$. This is in contradiction with former proposals that the transverse transport detects the formation of incoherent Cooper pairs in the pseudogap state. Conversely, the analysis of the data using a phenomenological angular dependent scattering rate clearly allows to distinguish between underdoped and overdoped states, and we propose that the maximum in $R_H(T)$ simply arises due to the combination of a large isotropic scattering rate and an anisotropic temperature dependent one

Binary Stellar Population Synthesis Model

Using Yunnan evolutionary population synthesis (EPS) models, we present integrated colours, integrated spectral energy distributions (ISEDs) and absorption-line indices defined by the Lick Observatory image dissector scanner (Lick/IDS) system, for an extensive set of instantaneous-burst binary stellar populations (BSPs) with interactions. By comparing the results for populations with and without interactions we show that the inclusion of binary interactions makes the appearance of the population substantially bluer. This effect raises the derived age and metallicity of the population. To be used in the studies of modern spectroscopic galaxy surveys at intermediate/high spectral resolution, we also present intermediate- (3A) and high-resolution (~0.3A) ISEDs and Lick/IDS absorption-line indices for BSPs. To directly compare with observations the Lick/IDS absorption indices are also presented by measuring them directly from the ISEDs.Comment: 2 pages 2 figure

Resistance noise in Bi_2Sr_2CaCu_2O8+δ_{8+\delta}

The resistance noise in a Bi_2Sr_2CaCu_2O$_{8+\delta}$ thin film is found to increase strongly in the underdoped regime. While the increase of the raw resistance noise with decreasing temperature appears to roughly track the previously reported pseudogap temperature for this material, standard noise analysis rather suggests that the additional noise contribution is driven by the proximity of the superconductor-insulator transition

The Effect of Binary Interactions in Infrared Passbands

We present the integrated J, H, K, L, M and N magnitudes and the colours involving infrared bands, for an extensive set of instantaneous-burst binary stellar populations (BSPs) by using evolutionary population synthesis (EPS). By comparing the results for BSPs WITH and WITHOUT binary interactions we show that the inclusion of binary interactions makes the magnitudes of populations larger (fainter) and the integrated colours smaller (bluer) for t > 1Gyr. Also, we compare our model magnitudes and colours with those of Bruzual & Charlot (2003, hereafter BC03) and Maraston (2005, hereafter M05). At last, we compare these model broad colours with Magellanic Clouds globular clusters (GCs) and Milky Way GCs. In (V-R)-[Fe/H] and (V-I)-[Fe/H] diagrams it seems that our models match the observations better than those of BC03 and M05.Comment: 2 page 3 figure

Electron transport in interacting hybrid mesoscopic systems

A unified theory for the current through a nanoscale region of interacting electrons connected to two leads which can be either ferromagnet or superconductor is presented, yielding Meir-Wingreen-type formulas when applied to specific circumstances. In such a formulation, the requirement of gauge invariance for the current is satisfied automatically. Moreover, one can judge unambiguously what quantities can be measured in the transport experiment

LLAGN and jet-scaling probed with the EVN

Accreting black holes on all mass scales (from stellar to supermassive) appear to follow a nonlinear relation between X-ray luminosity, radio luminosity and BH mass, indicating that similar physical processes drive the central engines in X-ray binaries and active galactic nuclei (AGN). However, in recent years an increasing number of BH systems have been identified that do not fit into this scheme. These outliers may be the key to understand how BH systems are powered by accretion. Here we present results from EVN observations of a sample of low-luminosity AGN (LLAGN) with known mass that have unusually high radio powers when compared with their X-ray luminosity.Comment: Presented at the 11th EVN Symposium, Bordeaux, France, 2012 October 9-12. Six pages, including a figure and a table. Final, accepted versio

Current dependent fluctuations in a Bi2_2Sr2_2CuO6+δ_{6+\delta} thin film

The current dependence of the excess conductivity is measured up to $\simeq 3 T_c$ for a Bi$_2$Sr$_2$CuO$_{6+\delta}$ thin film, as a function of doping. It is found to be anomalously sensitive to the transport current and to behave as a universal function of $T/T_c$ in the whole doping range. We discuss these results in the perspective of a granular superconductor with a gapless-like behavior