Three-Color Entanglement Coelho, A.S; Barbosa, F.A.S; Cassemiro, K.N ...
Science (American Association for the Advancement of Science),
11/2009, Letnik:
326, Številka:
5954
Journal Article
Recenzirano
Odprti dostop
Entanglement is an essential quantum resource for the acceleration of information processing as well as for sophisticated quantum communication protocols. Quantum information networks are expected to ...convey information from one place to another by using entangled light beams. We demonstrated the generation of entanglement among three bright beams of light, all of different wavelengths (532.251, 1062.102, and 1066.915 nanometers). We also observed disentanglement for finite channel losses, the continuous variable counterpart to entanglement sudden death.
We demonstrate, theoretically and experimentally, the generation of hexapartite modal entanglement by the optical parametric oscillator (OPO) operating above the oscillation threshold. We show that ...the OPO generates a rich structure of entanglement among sets of six optical sideband modes interacting through the nonlinear crystal. The class of quantum states thus produced can be controlled by a single parameter, the power of the external laser that pumps the system. Our platform allows for the generation of massive entanglement among many optical modes with well defined but vastly different frequencies, potentially bridging nodes of a multicolor quantum network.
We present two-dimensional (2D) mapping of the gas velocity field of the inner few hundred parsecs of six nearby active galaxies, using spectra obtained with the integral field unit of the Gemini ...Multi-Object Spectrograph instrument at the Gemini North telescope. In our previous paper, we reported the 2D mapping of the stellar kinematics extracted from the calcium triplet absorption lines. In this paper, we use the S iiiλ9069 emission line to obtain the flux distribution and kinematics of the gas in the narrow-line region (NLR). The gas emission is extended by a few hundred parsecs and its kinematics are dominated by rotation in the galaxy plane. Subtraction of the rotation component reveals outflows along the NLR which show spatial correlation with radio structures seen in Very Large Array radio 3.6 and 20 cm flux images, suggesting that the radio jet is pushing the circumnuclear interstellar medium. This interpretation is also supported by the observation of high-velocity dispersion (σ≥ 500 km s−1) structures in association with the outflowing gas. The gas outflows and radio jets are oriented at random angles relative to the galaxy major axis, indicating that they are not launched perpendicularly to the galaxy plane. Slicing the emission-line profiles into velocity channels, we create maps of the NLR gas distribution at different radial velocities. In at least half of our sample, the highest velocities are observed close to the nucleus suggesting that the emitting gas is decelerating outwards, from projected blueshifts exceeding 400 km s−1 to values of 100–200 km s−1 at 100–200 pc from the nucleus. We have estimated mass outflow rates in the NLR of ≈1 to 50 × 10−3 M⊙ yr−1, which are ≈10–20 times the accretion rate necessary to feed the active nucleus. The kinetic energy of the ouflow is estimated to be 4–5 orders of magnitude smaller than the bolometric luminosity. Assuming kinetic energy transfer between the radio jet and the NLR outflows, the mass ejection rate in the radio jet is 5–6 orders of magnitude smaller than the mass accretion rate necessary to feed the nuclear supermassive black hole.
Given the importance of dissolved organic matter (DOM) in
the carbon cycling of aquatic ecosystems, information on its seasonal
variability is crucial. In this study we assess the use of
optical ...absorption indices available in the literature based on in situ data to both characterize the
seasonal variability of DOM in a highly complex environment and for
application in large-scale studies using remote sensing data. The study area
comprises four lakes located in the Mamirauá Sustainable Development
Reserve (MSDR). Samples for the determination of colored dissolved organic
matter (CDOM) and measurements of remote sensing reflectance (Rrs) were
acquired in situ. The Rrs was used to simulate the response of the visible
bands of the Sentinel-2 MultiSpectral Instrument (MSI), which was used in the
proposed models. Differences between lakes were tested using the CDOM
indices. The results highlight the role of the flood pulse in the DOM
dynamics at the floodplain lakes. The validation results show that the use of the absorption coefficient of CDOM
(aCDOM) as a proxy of the spectral slope between 275 and 295 nm (S275–295) during rising water is worthwhile,
demonstrating its potential application to Sentinel-2 MSI imagery data for
studying DOM dynamics on the large scale.
We map the kinematics of the inner (200 pc) narrow-line region (NLR) of the Seyfert 2 galaxy NGC 1068 using the instrument Near-infrared Integral Field Spectrograph and adaptive optics at the Gemini ...North telescope. Channel maps and position–velocity diagrams are presented at a spatial resolution of ≅8 pc and spectral resolution ∼5300 in the emission lines Fe ii λ1.644 μm, H2 λ2.122 μm and Brγ. The Fe ii emission line provides a better coverage of the NLR outflow than the previously used O iii λ5007 emission line, extending beyond the area of the bipolar cone observed in Brγ and O iii. This is mainly due to the contribution of the redshifted channels to the north-east of the nucleus, supporting its origin in a partial ionized zone with additional contribution from shocks of the outflowing gas with the galactic disc. We modelled the kinematics and geometry of the Fe ii emitting gas finding good agreement with the data for outflow models with conical and lemniscate (or hourglass) geometry. We calculate a mass outflow rate of
$1.9^{+2}_{-1}$
M⊙ yr−1 but a power for the outflow of only 0.08 per cent L
Bol. The molecular (H2) gas kinematics is completely distinct from that of Fe ii and Brγ, showing radial expansion in an off-centred ∼100 pc radius ring in the galaxy plane. The expansion velocity decelerates from ≈200 km s−1 in the inner border of the ring to approximately zero at the outer border where our previous studies found a 10 Myr stellar population.
The presentation of real-world images can swiftly engage processing mechanisms within specific brain regions and neural pathways. In this study, we explore the effects of fear and psychopathological ...symptoms on neural processing of realistic stimuli during a free viewing naturalistic task in a sample of adolescents (11–16y). Thirty-one participants performed an experimental task consisting of the visualization of animal pictures according to three conditions - Snakes, Spiders, and Dogs - during EEG recordings. Dimensions of fear and psychopathological symptoms were previously assessed through The Fear Survey Schedule for Children- Revised and the Brief Symptom Inventory. Earlier and later visual processing was analyzed through ERP components’ peak amplitudes. The results show a robust effect of psychopathology-related dimensions in the visual processing of naturalistic images, suggesting an increase of neural activity at later stages of visual processing (at the N200 time window) in symptomatic adolescents, corroborating the role of psychopathological symptoms in modulating neural responses to naturalistic images, and also guiding clinicians by providing additional data on how symptomatic adolescents perceive and process reality.
•Higher scores of psychopathological symptoms in adolescents enhance later visual processing of naturalistic images.•The visualization of different types of animals interacts with psychopathological symptoms, modulating N200 amplitudes.•Reduced Fear of Danger, Death and Injuries heightens later visual processing for pictures of Spiders and Dogs.
In this paper, we propose a new sorbent that is able to extract metal ions directly from untreated biological fluids, simultaneously excluding all proteins from these samples. The sorbent was ...obtained through the modification of carbon nanotubes (CNTs) with an external bovine serum albumin (BSA) layer, resulting in restricted access carbon nanotubes (RACNTs). The BSA layer was fixed through the interconnection between the amine groups of the BSA using glutaraldehyde as cross-linker. When a protein sample is percolated through a cartridge containing RACNTs and the sample pH is higher than the isoelectric point of the proteins, both proteins from the sample and the BSA layer are negatively ionized. Thus, an electrostatic repulsion prevents the interaction between the proteins from the sample on the RACNTs surface. At the same time, metal ions are adsorbed in the CNTs (core) after their passage through the chains of proteins. The Cd2+ ion was selected for a proof-of-principle case to test the suitability of the RACNTs due to its toxicological relevance. RACNTs were able to extract Cd2+ and exclude almost 100% of the proteins from the human serum samples in an online solid-phase extraction system coupled with thermospray flame furnace atomic absorption spectrometry. The limits of detection and quantification were 0.24 and 0.80μgL−1, respectively. The sampling frequency was 8.6h−1, and the intra- and inter-day precisions at the 0.80, 15.0, and 30.0μgL−1 Cd2+ levels were all lower than 10.1% (RSD). The recoveries obtained for human blood serum samples fortified with Cd2+ ranged from 85.0% to 112.0%. The method was successfully applied to analyze Cd2+ directly from six human blood serum samples without any pretreatment, and the observed concentrations ranged from <LOQ to 2.52µgL−1.
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•Restricted access carbon nanotubes (RACNTs) were synthesized.•RACNTs were able to extract cadmium and exclude all proteins from the samples.•Proteins were excluded by electrostatic repulsion.•RACNTs were employed to extract cadmium directly from untreated human serum samples.
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![Modelling the [Fe ii] λ1.64...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0035-8711_1365-8711_1365-2966/small "Modelling the [Fe ii] λ1.644 μm outflow and comparison with H2 and H+ kinematics in the inner 200 pc of NGC 1068")
