We compute the quantum correlation quantum discord (QD) and the entanglement (EOF) between nearest-neighbor qubits (spin-1/2) in an infinite chain described by the Heisenberg model (XXZ Hamiltonian) ...at finite temperatures. The chain is in the thermodynamic limit and thermalized with a reservoir at temperature T (canonical ensemble). We show that QD, in contrast to EOF and other thermodynamic quantities, spotlight the critical points associated with quantum phase transitions (QPT) for this model even at finite T. This remarkable property of QD may have important implications for experimental characterization of QPTs when one is unable to reach temperatures below which a QPT can be seen.
Review of particle physics Hagiwara, K; Nakamura, K; Amsler, C ...
Physical review. D, Particles and fields,
07/2002, Letnik:
66, Številka:
1
Journal Article
Recenzirano
This biennial Review summarizes much of Particle Physics Using data from previous editions, plus 2205 new measurements from 667 papers, we list, evaluate, and average measured properties of gauge ...bosons, leptons, quarks, mesons, and baryons We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles All the particle properties and search limits are listed in Summary Tables We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics This edition features expanded coverage of CP violation in B mesons and of neutrino oscillations For the first time we cover searches for evidence of extra dimensions (both in the particle listings and in a new review) Another new review is on Grand Unified Theories A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review All tables, listings, and reviews (and errata) are also available on the Particle Data Group website http //pdg 1b1 gov.
Review of Particle Physics
The European physical journal. C, Particles and fields,
03/1998, Letnik:
3, Številka:
1-4
Journal Article
Recenzirano
Odprti dostop
This biennial Review summarizes much of Particle Physics. Using data from previous editions, plus 1600 new measurements from 550 papers, we list, evaluate, and average measured properties of gauge ...bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http: //pdg. lbl. gov.
Fits for K L 0 CP-Violation parameters Trippe, T. G.
The European physical journal. C, Particles and fields,
3/2000, Letnik:
15, Številka:
1-4
Journal Article
The central parsec around the supermassive black hole in the Galactic center (GC) hosts more than 100 young and massive stars. Outside the central cusp (R ~ 1'') the majority of these O and ...Wolf-Rayet (W-R) stars reside in a main clockwise system, plus a second, less prominent disk or streamer system at large angles with respect to the main system. Here we present the results from new observations of the GC with the AO-assisted near-infrared imager NACO and the integral field spectrograph SINFONI on the ESO/VLT. These include the detection of 27 new reliably measured W-R/O stars in the central 12'' and improved measurements of 63 previously detected stars, with proper motion uncertainties reduced by a factor of 4 compared to our earlier work. Based on the sample of 90 well measured W-R/O stars, we develop a detailed statistical analysis of their orbital properties and orientations. We show that half of the W-R/O stars are compatible with being members of a clockwise rotating system. The rotation axis of this system shows a strong transition from the inner to the outer regions as a function of the projected distance from Sgr A*. The main clockwise system either is either a strongly warped single disk with a thickness of about 10DG, or consists of a series of streamers with significant radial variation in their orbital planes. Eleven out of 61 clockwise moving stars have an angular separation of more than 30DG from the local angular momentum direction of the clockwise system. The mean eccentricity of the clockwise system is 0.36 - 0.06. The distribution of the counterclockwise W-R/O star is not isotropic at the 98% confidence level. It is compatible with a coherent structure such as stellar filaments, streams, small clusters or possibly a disk in a dissolving state: 10 out of 29 counterclockwise moving W-R/O stars have an angular separation of more than 30DG from the local angular momentum direction of the counterclockwise system. The observed disk warp and the steep surface density distribution favor in situ star formation in gaseous accretion disks as the origin of the young massive stars.
Genome-wide association studies (GWASs) are a valuable tool for understanding the biology of complex human traits and diseases, but associated variants rarely point directly to causal genes. In the ...present study, we introduce a new method, polygenic priority score (PoPS), that learns trait-relevant gene features, such as cell-type-specific expression, to prioritize genes at GWAS loci. Using a large evaluation set of genes with fine-mapped coding variants, we show that PoPS and the closest gene individually outperform other gene prioritization methods, but observe the best overall performance by combining PoPS with orthogonal methods. Using this combined approach, we prioritize 10,642 unique gene-trait pairs across 113 complex traits and diseases with high precision, finding not only well-established gene-trait relationships but nominating new genes at unresolved loci, such as LGR4 for estimated glomerular filtration rate and CCR7 for deep vein thrombosis. Overall, we demonstrate that PoPS provides a powerful addition to the gene prioritization toolbox.
We report results from a deep polarization imaging of the nearby radio galaxy 3C 84 (NGC 1275). The source was observed with the Global Millimeter VLBI Array (GMVA) at 86 GHz at an ultrahigh angular ...resolution of 50 μas (corresponding to ∼200Rs). We also add complementary multiwavelength data from the Very Long Baseline Array (VLBA; 15 and 43 GHz) and from the Atacama Large Millimeter/submillimeter Array (ALMA; 97.5, 233.0 and 343.5 GHz). At 86 GHz, we measured a fractional linear polarization of ∼2% in the VLBI core region. The polarization morphology suggests that the emission is associated with an underlying limb-brightened jet. The fractional linear polarization is lower at 43 and 15 GHz (∼0.3−0.7% and <0.1%, respectively). This suggests an increasing linear polarization degree toward shorter wavelengths on VLBI scales. We also obtain a large rotation measure (RM) of ∼105–6 rad m2 in the core at ≳43 GHz. Moreover, the VLBA 43 GHz observations show a variable RM in the VLBI core region during a small flare in 2015. Faraday depolarization and Faraday conversion in an inhomogeneous and mildly relativistic plasma could explain the observed linear polarization characteristics and the previously measured frequency dependence of the circular polarization. Our Faraday depolarization modeling suggests that the RM most likely originates from an external screen with a highly uniform RM distribution. To explain the large RM value, the uniform RM distribution and the RM variability, we suggest that the Faraday rotation is caused by a boundary layer in a transversely stratified jet. Based on the RM and the synchrotron spectrum of the core, we provide an estimate for the magnetic field strength and the electron density of the jet plasma.
Sagittarius A*, the supermassive compact object at the center of the Galaxy, exhibits outbursts in the near infrared (NIR) and X-ray domains. These flares are likely due to energetic events very ...close to the central object, on a scale of a few Schwarzschild radii. Optical interferometry will soon be able to provide astrometry with an accuracy of this order (10 is a subset of as). In this article, we use recent photometric NIR data observed with the adaptive optics system NACO at the Very Large Telescope combined with simulations in order to deploy a method to test the nature of the flares and to predict the possible outcome of observations with the Very Large Telescope Interferometer. To accomplish this we implement a hot-spot model and investigate its appearance for a remote observer in terms of light curves and centroid tracks, based on general relativistic ray-tracing methods. First, we use a simplified model of a small steady source in order to investigate the relativistic effects qualitatively. A more realistic scenario is then being developed by fitting our model to existing flare data. While indications for the spin of the black hole and multiple images due to lensing effects are marginal in the light curves, astrometric measurements offer the possibility to reveal these high-order general relativistic effects. This study makes predictions on these astrometric measurements and leads us to the conclusion that future infrared interferometers will be able to detect proper motion of hot spots in the vicinity of Sagittarius A*.
Why humans deviate from rational choice Hewig, Johannes; Kretschmer, Nora; Trippe, Ralf H. ...
Psychophysiology,
April 2011, Letnik:
48, Številka:
4
Journal Article
Recenzirano
Rational choice theory predicts that humans always optimize the expected utility of options when making decisions. However, in decision‐making games, humans often punish their opponents even when ...doing so reduces their own reward. We used the Ultimatum and Dictator games to examine the affective correlates of decision‐making. We show that the feedback negativity, an event‐related brain potential that originates in the anterior cingulate cortex that has been related to reinforcement learning, predicts the decision to reject unfair offers in the Ultimatum game. Furthermore, the decision to reject is positively related to more negative emotional reactions and to increased autonomic nervous system activity. These findings support the idea that subjective emotional markers guide decision‐making and that the anterior cingulate cortex integrates instances of reinforcement and punishment to provide such affective markers.
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