Efficient single-photon-assisted entanglement concentration for partially entangled photon pairs

We present two realistic entanglement concentration protocols (ECPs) for pure partially entangled photons. A partially entangled photon pair can be concentrated to a maximally entangled pair with only an ancillary single photon in a certain probability, while the conventional ones require two copies of partially entangled pairs at least. Our first protocol is implemented with linear optics and the second one is implemented with cross-Kerr nonlinearities. Compared with other ECPs, they do not need to know the accurate coefficients of the initial state. With linear optics, it is feasible with current experiment. With cross-Kerr nonlinearities, it does not require the sophisticated single-photon detectors and can be repeated to get a higher success probability. Moreover, the second protocol can get the higher entanglement transformation efficiency and it maybe the most economical one by far. Meanwhile, both of protocols are more suitable for multi-photon system concentration, because they need less operations and classical communications. All these advantages make two protocols be useful in current long-distance quantum communications

Efficient two-step entanglement concentration for arbitrary W states

We present two two-step practical entanglement concentration protocols (ECPs) for concentrating an arbitrary three-particle less-entangled W state into a maximally entangled W state assisted with single photons. The first protocol uses the linear optics and the second protocol adopts the cross-Kerr nonlinearity to perform the protocol. In the first protocol, based on the post-selection principle, three parties say Alice, Bob and Charlie in different distant locations can obtain the maximally entangled W state from the arbitrary less-entangled W state with a certain success probability. In the second protocol, it dose not require the parties to posses the sophisticated single-photon detectors and the concentrated photon pair can be retained after performing this protocol successfully. Moreover, the second protocol can be repeated to get a higher success probability. Both protocols may be useful in practical quantum information applications.Comment: 10 pages, 4 figure

Epimedium brevicornu Maxim extract shows protective activity against Alzheimer's disease in mice

Purpose: To investigate the protective effect of Epimedium brevicornu Maxim extract (EBME) against Alzheimer's disease in 3xTg-AD mice. Methods: The cognitive function of 3xTg-AD mice was assessed using Morris water maze test. The levels of amyloid beta deposits and NeuN in the mouse hippocampus were evaluated by immunohistochemistry. Brain neurotrophic-derived factor (BDNF) and tyrosine kinase B (TrkB) expressions were examined by western blot analysis. Results: EBME treatment significantly ameliorated learning and memory deficits in AD mice, as shown by the increased time spent in the target zone during probe tests. Compared with the 3xTg-AD mice (8.4 ± 1.1 s), the escape latency in animals treated with 600 mg/kg EBME (21.5 ± 1.1 s) was significantly increased (p < 0.01). In addition, EBME significantly decreased Aβ deposits, increased NeuN-positive cells, and upregulated the expressions of BDNF (1.5 ± 0.2, p < 0.05) and TrkB (1.6 ± 0.2, p < 0.05) in the 3xTg AD mice. Conclusion: EBME treatment may be a useful therapeutic strategy for managing memory impairment