11,037 research outputs found
Spin-orbit induced chirality of Andreev states in Josephson junctions
We study Josephson junctions (JJs) in which the region between the two
superconductors is a multichannel system with Rashba spin-orbit coupling (SOC)
where a barrier or a quantum point contact (QPC) is present. These systems
might present unconventional Josephson effects such as Josephson currents for
zero phase difference or critical currents that \textit{depend on} the current
direction. Here, we discuss how the spin polarizing properties of the system in
the normal state affect the spin characteristic of the Andreev bound states
inside the junction. This results in a strong correlation between the spin of
the Andreev states and the direction in which they transport Cooper pairs.
While the current-phase relation for the JJ at zero magnetic field is
qualitatively unchanged by SOC, in the presence of a weak magnetic field a
strongly anisotropic behavior and the mentioned anomalous Josephson effects
follow. We show that the situation is not restricted to barriers based on
constrictions such as QPCs and should generically arise if in the normal system
the direction of the carrier's spin is linked to its direction of motion.Comment: 19 pages, 9 figures. To appear in PR
Gemini/GMOS photometry of intermediate-age star clusters in the Large Magellanic Cloud
We present Gemini South GMOS g,i photometry of 14 intermediate-age Large
Magellanic Cloud (LMC) star clusters, namely: NGC 2155, 2161, 2162, 2173, 2203,
2209, 2213, 2231, 2249, Hodge 6, SL 244, 505, 674, and 769, as part of a
continuing project to investigate the extended Main Sequence Turnoff (EMSTO)
phenomenon. Extensive artificial star tests were made over the observed field
of view. These tests reveal the observed behaviour of photometric errors with
magnitude and crowding. The cluster stellar density radial profiles were traced
from star counts over the extent of the observed field. We adopt clus- ter
radii and build colour-magnitude diagrams (CMDs) with cluster features clearly
identified. We used the cluster (g,g-i) CMDs to estimate ages from the matching
of theoretical isochrones. The studied LMC clusters are confirmed to be
intermediate-age clusters, which range in age 9.10 < log(t) < 9.60. NGC 2162
and NGC 2249 look like new EMSTO candidates, in addition to NGC 2209, on the
basis of having dual red clumps.Comment: MNRAS, accepte
Two-fluid behavior of the Kondo lattice in the 1/N slave boson approach
It has been recently shown by Nakatsuji, Pines, and Fisk [S. Nakatsuji, D.
Pines, and Z. Fisk, Phys. Rev. Lett. 92, 016401 (2004)] from the
phenomenological analysis of experiments in Ce1-xLaxCoIn5 and CeIrIn5 that
thermodynamic and transport properties of Kondo lattices below coherence
temperature can be very successfully described in terms of a two-fluid model,
with Kondo impurity and heavy electron Fermi liquid contributions. We analyze
thermodynamic properties of Kondo lattices using 1/N slave boson treatment of
the periodic Anderson model and show that these two contributions indeed arise
below the coherence temperature. We find that the Kondo impurity contribution
to thermodynamics corresponds to thermal excitations into the flat portion of
the energy spectrum.Comment: 7 pages, 2 figure
Highest weight state description of the isotropic spin-1 chain
We introduce an overcomplete highest weight state basis as a calculational
tool for the description of the isotropic spin-1 chain with bilinear exchange
coupling J1 and biquadratic coupling J2. The ground state can be expressed
exactly at the three special points in the phase diagram where the Hamiltonian
corresponds to a sum of nearest neighbor total spin projection operators
(J1=0>J2, J1=-J2<0, and J1=-J2/3<0). In particular, at the phase transition
point J1=-J2<0 it is possible to exactly compute the ground states, excited
states, expectation values, and correlation functions by using the new total
spin basis.Comment: 8 pages, 1 figure, the most recent version can be found at
http://www.physik.uni-kl.de/eggert/papers
The Dividend Policy of German Firms
Abstract: German firms pay out a lower proportion of their cash flows, but a higher proportion of their published profits than UK and US firms. We estimate partial adjustment models and report two major findings. First, German firms base their dividend decisions on cash flows rather than published earnings as (i) published earnings do not correctly reflect performance because German firms retain parts of their earnings to build up legal reserves, (ii) German accounting is conservative, (iii) published earnings are subject to more smoothing than cash flows. Second, to the opposite of UK and US firms, German firms have more flexible dividend policies as they are willing to cut the dividend when profitability is only temporarily down.
Avaliação técnico-econômica do controle de gramÃneas em milho em área de várzea.
bitstream/item/30282/1/boletim-34.pd
Washington photometry of five star clusters in the Large Magellanic Cloud
Aims. We present CCD photometry in the Washington system C and T1 passbands down to T1 ∼ 22.5 in the fields of NGC 1697, SL 133, NGC 1997, SL 663, and OHSC 28, five mostly unstudied star clusters in the LMC. Methods. Cluster radii were estimated from star counts in appropriate-sized boxes distributed throughout the entire observed fields. We perform a detailed analysis of the field star contamination and derive cluster colour-magnitude diagrams (CMDs). Based on the
best fits of isochrones computed by the Padova group to the (T1, C − T1) CMDs, the δ(T1) index and the Standard Giant Branch procedure, we derive metallicities and ages for the five clusters. We combine our sample with clusters with ages and metallicities on a similar scale and examine relationships between position in the LMC, age and metallicity. Results. With the exception of NGC 1697 (age = 0.7 Gyr, [Fe/H] = 0.0 dex), the remaining four clusters are of intermediate-age (from 2.2 to 3.0 Gyr) and relatively metal-poor ([Fe/H] = –0.7 dex). The cluster and field age-metallicty realtions show evidence for a metallicity offset but do overlap, particularly on the upper envelope side of the cluster age-metallicity relation. Conclusions. We confirm previous results that clusters younger than ∼1 Gyr were formed during an outside-in process; this occurred after a burst of cluster formation that took place mainly in the outer disk and peaked at ∼2 Gyr ago.Fil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciónes CientÃficas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de AstronomÃa y FÃsica del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de AstronomÃa y FÃsica del Espacio; ArgentinaFil: Geisler, D.. Universidad de Concepción; ChileFil: Sarajedini, A.. University of Florida; Estados UnidosFil: Gallart, C.. Instituto de AstrofÃsica de Canarias,; Españ
Superconductivity and charge carrier localization in ultrathin bilayers
/ (LSCO15/LCO) bilayers
with a precisely controlled thickness of N unit cells (UCs) of the former and M
UCs of the latter ([LSCO15\_N/LCO\_M]) were grown on (001)-oriented {\slao}
(SLAO) substrates with pulsed laser deposition (PLD). X-ray diffraction and
reciprocal space map (RSM) studies confirmed the epitaxial growth of the
bilayers and showed that a [LSCO15\_2/LCO\_2] bilayer is fully strained,
whereas a [LSCO15\_2/LCO\_7] bilayer is already partially relaxed. The
\textit{in situ} monitoring of the growth with reflection high energy electron
diffraction (RHEED) revealed that the gas environment during deposition has a
surprisingly strong effect on the growth mode and thus on the amount of
disorder in the first UC of LSCO15 (or the first two monolayers of LSCO15
containing one plane each). For samples grown in pure
gas (growth type-B), the first LSCO15 UC next to the SLAO
substrate is strongly disordered. This disorder is strongly reduced if the
growth is performed in a mixture of and gas
(growth type-A). Electric transport measurements confirmed that the first UC of
LSCO15 next to the SLAO substrate is highly resistive and shows no sign of
superconductivity for growth type-B, whereas it is superconducting for growth
type-A. Furthermore, we found, rather surprisingly, that the conductivity of
the LSCO15 UC next to the LCO capping layer strongly depends on the thickness
of the latter. A LCO capping layer with 7~UCs leads to a strong localization of
the charge carriers in the adjacent LSCO15 UC and suppresses superconductivity.
The magneto-transport data suggest a similarity with the case of weakly hole
doped LSCO single crystals that are in a so-called {"{cluster-spin-glass
state}"
Ação de regulador do metabolismo de etileno sobre a produtividade de soja cultivada em terras baixas.
bitstream/item/30414/1/boletim-68.pd
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