Einstein-Podolsky-Rosen correlations and Bell correlations in the simplest scenario

Einstein-Podolsky-Rosen (EPR) steering is an intermediate type of quantum nonlocality which sits between entanglement and Bell nonlocality. A set of correlations is Bell nonlocal if it does not admit a local hidden variable (LHV) model, while it is EPR nonlocal if it does not admit a local hidden variable-local hidden state (LHV-LHS) model. It is interesting to know what states can generate EPR-nonlocal correlations in the simplest nontrivial scenario, that is, two projective measurements for each party sharing a two-qubit state. Here we show that a two-qubit state can generate EPR-nonlocal full correlations (excluding marginal statistics) in this scenario if and only if it can generate Bell-nonlocal correlations. If full statistics (including marginal statistics) is taken into account, surprisingly, the same scenario can manifest the simplest one-way steering and the strongest hierarchy between steering and Bell nonlocality. To illustrate these intriguing phenomena in simple setups, several concrete examples are discussed in detail, which facilitates experimental demonstration. In the course of study, we introduce the concept of restricted LHS models and thereby derive a necessary and sufficient semidefinite-programming criterion to determine the steerability of any bipartite state under given measurements. Analytical criteria are further derived in several scenarios of strong theoretical and experimental interest.Comment: New results added, 13 pages, 3 figures; published in Phys. Rev.

Complex quantum network model of energy transfer in photosynthetic complexes

The quantum network model with real variables is usually used to describe the excitation energy transfer (EET) in the Fenna-Matthews-Olson(FMO) complexes. In this paper we add the quantum phase factors to the hopping terms and find that the quantum phase factors play an important role in the EET. The quantum phase factors allow us to consider the space structure of the pigments. It is found that phase coherence within the complexes would allow quantum interference to affect the dynamics of the EET. There exist some optimal phase regions where the transfer efficiency takes its maxima, which indicates that when the pigments are optimally spaced, the exciton can pass through the FMO with perfect efficiency. Moreover, the optimal phase regions almost do not change with the environments. In addition, we find that the phase factors are useful in the EET just in the case of multiple-pathway. Therefore, we demonstrate that, the quantum phases may bring the other two factors, the optimal space of the pigments and multiple-pathway, together to contribute the EET in photosynthetic complexes with perfect efficiency.Comment: 8 pages, 9 figure

Electron-nuclear entanglement in the cold lithium gas

We study the ground-state entanglement and thermal entanglement in the hyperfine interaction of the lithium atom. We give the relationship between the entanglement and both temperature and external magnetic fields.Comment: 7 pages, 3 figure

Major emerging and re-emerging zoonoses in China: a matter of global health and socioeconomic development for 1.3 billion

SummaryEmerging and re-emerging zoonoses are a significant public health concern and cause considerable socioeconomic problems globally. The emergence of severe acute respiratory syndrome (SARS), highly pathogenic avian influenza (HPAI) H5N1, avian influenza H7N9, and severe fever with thrombocytopenia syndrome (SFTS), and the re-emergence of rabies, brucellosis, and other zoonoses have had a significant effect on the national economy and public health in China, and have affected other countries. Contributing factors that continue to affect emerging and re-emerging zoonoses in China include social and environmental factors and microbial evolution, such as population growth, urbanization, deforestation, livestock production, food safety, climate change, and pathogen mutation. The Chinese government has devised new strategies and has taken measures to deal with the challenges of these diseases, including the issuing of laws and regulations, establishment of disease reporting systems, implementation of special projects for major infectious diseases, interdisciplinary and international cooperation, exotic disease surveillance, and health education. These strategies and measures can serve as models for the surveillance and response to continuing threats from emerging and re-emerging zoonoses in other countries