Quantum state transmission via a spin ladder as a robust data bus

We explore the physical mechanism to coherently transfer the quantum information of spin by connecting two spins to an isotropic antiferromagnetic spin ladder system as data bus. Due to a large spin gap existing in such a perfect medium, the effective Hamiltonian of the two connected spins can be archived as that of Heisenberg type, which possesses a ground state with maximal entanglement. We show that the effective coupling strength is inversely proportional to the distance of the two spins and thus the quantum information can be transferred between the two spins separated by a longer distance, i.e. the characteristic time of quantum state transferring linearly depends on the distance.Comment: 7 pages, 5 figures, 1 tabl

Higher bottom and bottom-strange mesons

Motivated by the recent observation of the orbital excitation $B(5970)$ by CDF collaboration, we have performed a systematical study of the mass spectrum and strong decay patterns of the higher $B$ and $B_s$ mesons. Hopefully the present investigation may provide valuable clues to further experimental exploration of these intriguing excited heavy mesons.Comment: 13 pages, 11 figures, 10 tables. More discussions and references added. Accepted by Phys. Rev.

Comparison of a unified analysis approach for family and unrelated samples with the transmission-disequilibrium test to study associations of hypertension in the Framingham Heart Study

Population stratification is one of the major causes of spurious associations in association studies. A unified association approach based on principal-component analysis can overcome the effect of population stratification, as well as make use of both family and unrelated samples combined to increase power (family-case-control, or FamCC). In this study, we compared FamCC and the transmission-disequilibrium test (TDT) using data on hypertension, systolic blood pressure, and diastolic blood pressure in the Framingham Heart Study. Our study indicated FamCC has reasonable type I error for both the unrelated sample and the family sample for all three traits. For these three traits, we found results from FamCC were inconsistent with those from the TDT. We discuss the reasons for this inconsistency. After correcting for multiple tests, we did not detect any significant single-nucleotide polymorphisms by either FamCC or the TDT

Robust 3D face landmark localization based on local coordinate coding

In the 3D facial animation and synthesis community, input faces are usually required to be labeled by a set of landmarks for parameterization. Because of the variations in pose, expression and resolution, automatic 3D face landmark localization remains a challenge. In this paper, a novel landmark localization approach is presented. The approach is based on local coordinate coding (LCC) and consists of two stages. In the first stage, we perform nose detection, relying on the fact that the nose shape is usually invariant under the variations in the pose, expression, and resolution. Then, we use the iterative closest points algorithm to find a 3D affine transformation that aligns the input face to a reference face. In the second stage, we perform resampling to build correspondences between the input 3D face and the training faces. Then, an LCC-based localization algorithm is proposed to obtain the positions of the landmarks in the input face. Experimental results show that the proposed method is comparable to state of the art methods in terms of its robustness, flexibility, and accuracy

Characterizing entanglement by momentum-jump in the frustrated Heisenberg ring at quantum phase transition

We study the pairwise concurrences, a measure of entanglement, of the ground states for the frustrated Heisenberg ring to explore the relation between entanglement and quantum phase transition associated with the momentum jump. The groundstate concurrences between any two sites are obtained analytically and numerically. It shows that the summation of all possible pairwise concurrences is an appropriate candidate to depict the phase transition. We also investigate the role that the momentum takes in the jump of concurrence at the critical points. We find that an abrupt momentum change rusults in the maximal concurrence difference of two degenerate ground states.Comment: 7 pages, 5 figure

Hábitos alimenticios de Calanus sinicus (Crustacea: Copepoda) durante primavera y otoño en el mar Bohai, investigados mediante un índice de herbivoría

Pigment ingestion rate (PIR) and egg production rate (EPR) of the dominant copepod Calanus sinicus, as well as chlorophyll-a concentration and phytoplankton assemblages were measured in the Bohai Sea, North China in June 1997, October 1998 and May 1999. A herbivore index (H) was also calculated as the carbon specific ratio of PIR and EPR, in order to investigate its feeding habits in the spring and autumn phytoplankton bloom respectively. On average, chlorophyll-a concentration was relatively similar (1-1.34 mg m-3) in the three cruises, but PIR was quite different. It was 3.24 µg C female-1 d-1 in October, equivalent to one half of the PIR for June and one third of the PIR for May. Average EPR was highest in May, and quite similar during the other two months. According to H values, herbivorous feeding contributed 100% of the egg production of C. sinicus in June, 82.5% in May, but only 47.8% in October. It is possible that omnivorous feeding of C. sinicus in October was induced by a prevalence of large-sized diatoms and sufficient non-phytoplankton food resources during the autumn bloom period.La tasa de ingestión de pigmentos (PIR) y la tasa de producción de huevos (EPR) del copépodo dominante Calanus sinicus ha sido determinada, conjuntamente con la concentración de clorofila- a y la composición del fitoplancton, en el mar de Bohai, norte de China, en junio 1997, octubre 1998 y mayo 1999. Para investigar los hábitos alimenticios durante los blooms de fitoplancton de primavera y otoño se ha determinado un índice de herbivoría (H), calculado como el cociente de las tasas específicas PIR y EPR en carbono. En promedio, la concentración de clorofila-a fue relativamente similar (1-1,34 mg m-3) en las tres campañas oceanográficas. Pero los valores de PIR difirieron bastante, variando desde 3,24 μg C hembra-1 d-1 en octubre a valores un medio y un tercio de dicho valor, respectivamente, en junio y mayo. Los valores promedio de EPR fueron máximos en mayo, y bastante similares durante los otros dos meses. Según los valores del índice H obtenidos, la herbivoría contribuyó un 100% en la producción de huevos de C. sinicus en junio y un 82,5% en mayo, mientras que sólo explicó un 47,8% de la producción de huevos en octubre. este estudio sugiere que la alimentación omnivora de C. sinicus en octubre fue inducida por la prevalencia de diatomeas de gran tamaño y la presencia suficiente de alimento no fitoplanctónico durante el periodo del bloom otoñal.

Mixed Far-Field and Near-Field Source Localization Algorithm via Sparse Subarrays

Based on a dual-size shift invariance sparse linear array, this paper presents a novel algorithm for the localization of mixed far-field and near-field sources. First, by constructing a cumulant matrix with only direction-of-arrival (DOA) information, the proposed algorithm decouples the DOA estimation from the range estimation. The cumulant-domain quarter-wavelength invariance yields unambiguous estimates of DOAs, which are then used as coarse references to disambiguate the phase ambiguities in fine estimates induced from the larger spatial invariance. Then, based on the estimated DOAs, another cumulant matrix is derived and decoupled to generate unambiguous and cyclically ambiguous estimates of range parameter. According to the coarse range estimation, the types of sources can be identified and the unambiguous fine range estimates of NF sources are obtained after disambiguation. Compared with some existing algorithms, the proposed algorithm enjoys extended array aperture and higher estimation accuracy. Simulation results are given to validate the performance of the proposed algorithm