Effects of density-dependent quark mass on phase diagram of three-flavor quark matter

Considering the density dependence of quark mass, we investigate the phase transition between the (unpaired) strange quark matter and the color-flavor-locked matter, which are supposed to be two candidates for the ground state of strongly interacting matter. We find that if the current mass of strange quark $m_s$ is small, the strange quark matter remains stable unless the baryon density is very high. If $m_s$ is large, the phase transition from the strange quark matter to the color-flavor-locked matter in particular to its gapless phase is found to be different from the results predicted by previous works. A complicated phase diagram of three-flavor quark matter is presented, in which the color-flavor-locked phase region is suppressed for moderate densities.Comment: 4 figure

Strange sea asymmetry in nucleons

We evaluate the medium effects in nucleon which can induce an asymmetry of the strange sea. The short-distance effects determined by the weak interaction can give rise to $\delta m\equiv \Delta m_s-\Delta m_{\bar s}$ where $\Delta m_{s(\bar s)}$ is the medium-induced mass of strange quark by a few KeV at most, but the long-distance effects by strong interaction could be sizable.Comment: 4 pages and no figures, Talk presented at the Third Circum-Pan-Pacific Symposium on "High Energy Spin Physics", Oct. 8-13, 2001, Beijing, Chin

Generation of Narrow-Band Polarization-Entangled Photon Pairs for Atomic Quantum Memories

We report an experimental realization of a narrow-band polarization-entangled photon source with a linewidth of 9.6 MHz through cavity-enhanced spontaneous parametric down-conversion. This linewidth is comparable to the typical linewidth of atomic ensemble based quantum memories. Single-mode output is realized by setting a reasonable cavity length difference between different polarizations, using of temperature controlled etalons and actively stabilizing the cavity. The entangled property is characterized with quantum state tomography, giving a fidelity of 94% between our state and a maximally entangled state. The coherence length is directly measured to be 32 m through two-photon interference.Comment: 4 pages, 4 figure

A Study of Fermi-LAT GeV gamma-ray Emission towards the Magnetar-harboring Supernova Remnant Kesteven 73 and Its Molecular Environment

We report our independent GeV gamma-ray study of the young shell-type supernova remnant (SNR) Kes 73 which harbors a central magnetar, and CO-line millimeter observations toward the SNR. Using 7.6 years of Fermi-LAT observation data, we detected an extended gamma-ray source ("source A") with the centroid on the west of the SNR, with a significance of 21.6 sigma in 0.1-300 GeV and an error circle of 5.4 arcminute in angular radius. The gamma-ray spectrum cannot be reproduced by a pure leptonic emission or a pure emission from the magnetar, and thus a hadronic emission component is needed. The CO-line observations reveal a molecular cloud (MC) at V_LSR~90 km/s, which demonstrates morphological correspondence with the western boundary of the SNR brightened in multiwavelength. The 12CO (J=2-1)/12CO (J=1-0) ratio in the left (blue) wing 85-88 km/s is prominently elevated to ~1.1 along the northwestern boundary, providing kinematic evidence of the SNR-MC interaction. This SNR-MC association yields a kinematic distance 9 kpc to Kes 73. The MC is shown to be capable of accounting for the hadronic gamma-ray emission component. The gamma-ray spectrum can be interpreted with a pure hadronic emission or a magnetar+hadronic hybrid emission. In the case of pure hadronic emission, the spectral index of the protons is 2.4, very similar to that of the radio-emitting electrons, essentially consistent with the diffusive shock acceleration theory. In the case of magnetar+hadronic hybrid emission, a magnetic field decay rate >= 10^36 erg/s is needed to power the magnetar's curvature radiation.Comment: 7 figures, published in Ap

Access to Paediatric Essential Medicines: A Survey of Prices, Availability, Affordability and Price Components in Shaanxi Province, China

Objective: To evaluate the prices and availability of paediatric essential medicines in Shaanxi Province, China. Methods: Price and availability data for 28 paediatric essential medicines were collected from 60 public hospitals and 60 retail pharmacies in six areas of Shaanxi Province using a standardised methodology developed by the World Health Organization and Health Action International, during November to December 2012. Affordability was measured as the number of days’ wages required for the lowest-paid unskilled government worker to purchase standard treatments for common conditions. Data on medicine price components were collected from hospitals, wholesalers and distributors to obtain price mark-ups. Findings: The mean availabilities of originator brands (OBs) and lowest-priced generics (LPGs) were 10.8% and 27.3% in the public hospitals and 11.9% and 20.6% in the private pharmacies. The public procurement and retail prices were 2.25 and 2.59 times the international reference prices (IRPs) for three OBs, and 0.52 and 0.93 times for 20 LPGs. In the private sector, the final prices for OBs and LPGs were 3.89 and 1.25 times their IRPs. The final price in the private sector was 2.7% lower than in the public sector for OBs, and 14.1% higher for LPGs. Generally, standard treatments cost less than 1 day’s wages in both sectors. Distribution mark-ups applied to brand salbutamol in Xi'an was 65.5%, and up to 185.3% for generic. Cumulative mark-ups for LPGs in Ankang were also high, from 33% to 50%. The manufacturer’s selling price is the largest contributor to the final price in both areas. Conclusions: The government should approve a list of national paediatric essential medicines. The availability, price and affordability of these should be improved in both public hospitals and private pharmacies to enable children to obtain effective treatment. Measures should be taken to improve the efficiency of the centralised medicine purchasing system