Continuous-variable controlled-Z gate using an atomic ensemble

The continuous-variable controlled-Z gate is a canonical two-mode gate for universal continuous-variable quantum computation. It is considered as one of the most fundamental continuous-variable quantum gates. Here we present a scheme for realizing continuous-variable controlled-Z gate between two optical beams using an atomic ensemble. The gate is performed by simply sending the two beams propagating in two orthogonal directions twice through a spin-squeezed atomic medium. Its fidelity can run up to one if the input atomic state is infinitely squeezed. Considering the noise effects due to atomic decoherence and light losses, we show that the observed fidelities of the scheme are still quite high within presently available techniques.Comment: 7 pages, 3 figures, to appear in Physical Review

Fuzzy Weight Cluster-Based Routing Algorithm for Wireless Sensor Networks

Cluster-based protocol is a kind of important routing in wireless sensor networks. However, due to the uneven distribution of cluster heads in classical clustering algorithm, some nodes may run out of energy too early, which is not suitable for large-scale wireless sensor networks. In this paper, a distributed clustering algorithm based on fuzzy weighted attributes is put forward to ensure both energy efficiency and extensibility. On the premise of a comprehensive consideration of all attributes, the corresponding weight of each parameter is assigned by using the direct method of fuzzy engineering theory. Then, each node works out property value. These property values will be mapped to the time axis and be triggered by a timer to broadcast cluster headers. At the same time, the radio coverage method is adopted, in order to avoid collisions and to ensure the symmetrical distribution of cluster heads. The aggregated data are forwarded to the sink node in the form of multihop. The simulation results demonstrate that clustering algorithm based on fuzzy weighted attributes has a longer life expectancy and better extensibility than LEACH-like algorithms

Flash Flood Simulation Using Geomorphic Unit Hydrograph Method: Case Study Of Headwater Catchment Of Xiapu River Basin, China

The flash flood refers to flood produced by heavy local rainfalls and often occurs in mountainous areas. It is characterized by a quick rise of water level causing a great threat to the lives of those exposed. Many countries and regions face the threat of flash floods. However, some traditional hydrological models can hardly simulate the flash flood process well due to the lack of hydrological data and the insufficient understanding of complicated runoff mechanism in mountainous and hilly areas. According to this condition, a new hydrological model based on the framework of Xinanjiang model, widely used in humid and semi-humid regions in China, is presented to simulate flash flood. The highlight of new model is using the geomorphic unit hydrograph (GUH) method to simulate the overland flow process. This method has clear physical concept and can easily provide unit hydrographs of various time intervals only based on DEM data. This feature makes the method extremely valuable in ungauged catchment. The new presented hydrological model is used in the headwater catchment of Xiapu River basin and the results demonstrate that the computed data generally agrees well with the measured data and it can be treated as a useful tool for flash flood hazard assessment in mountainous catchment

31P NMR Investigation of the Superconductor LiFeP (Tc = 5 K)

We investigate the static and dynamic spin susceptibility of the 111 type Fe-based superconductor LiFeP with Tc ~ 5 K through the measurement of Knight shift 31K and the spin-lattice relaxation rate 1/T1 at 31P site by nuclear magnetic resonance. The constant 31K, small magnitudes of 1/T1T, along with the resistivity rho ~ T^2 all point to the weak spin correlations in LiFeP. 1/T1T display small enhancement toward Tc, indicating that the superconductivity is intimately correlated with the antiferromagnetic spin fluctuations.Comment: Accepted for publication in EP

Orthonormal basis of the octonionic analytic functions

AbstractBy confirming a conjecture proposed in Li and Peng (2001) [1], we obtain the orthonormal basis for the octonionic analytic functions

Closed-loop three-level charged quantum battery

Quantum batteries are energy storage or extract devices in a quantum system. Here, we present a closed-loop quantum battery by utilizing a closed-loop three-state quantum system in which the population dynamics depends on the three control fields and associated phases. We investigate the charging process of the closed-loop three-level quantum battery. The charging performance is greatly improved due to existence of the third field in the system to form a closed-contour interaction. Through selecting an appropriate the third control field, the maximum average power can be increased, even far beyond the most ideal maximum power value of non-closed-loop three-level quantum battery (corresponding to the most powerful charging obtainable with minimum quantum speed limit time and the maximum charging energy). We study the effect of global driving-field phase on the charging process and find the maximum extractable work (`ergotropy') and charging power vary periodically under different control field, with a period of $2\pi$. Possible experimental implementation in nitrogen-vacancy spin is discussed

A meta-analysis of Pemetrexed plus Platinum Chemotherapy versus Gemcitabine plus Platinum Chemotherapy for Advanced Non-small Cell Lung Cancer

Background and objective Whether pemetrexed plus platinum (PP) regimen is superior to gemcitabine plus platinum (GP) regimen for patients with advanced non-small cell lung cancer (NSCLC) is unclear. The aim of this study is to evaluate the efficacy and safety of PP versus GP regimens for patients with NSCLC. Methods We searched relevant randomized controlled trials (RCTs) from Pubmed, EMBASE, Cochrane Library, Chinese Journal Full-text Database, Chinese Biomedical Literature Database, Chinese Scientific Journals Full-text Database, and traced the related references to obtain the information that has not been found. We made quality assessment of qualified RCTs assessed by the exclusion and inclusion criteria and used RevMan 5.0 provided by the Cochrane Collaboration to perform meta-analysis. Results Four RCTs involving 2,235 patients were identified. There were no statistical differences between PP and GP regimens in one-year survival rate (OR=1.09, 95%CI: 0.91-1.29), the efficiency of disease (OR=1.00, 95%CI: 0.40-2.52), but overall survival (MD=0.26, 95%CI: 0.21-0.30), alopecia (OR=0.51, 95%CI: 0.39-0.66) and hematologic toxicity were significantly different. Conclusion The clinical efficiency of PP and GP regimens for advanced NSCLC was similar, but the side effects were different. The toxicity of PP regimen has the tendency to be more tolerable