Here, we report a proof-of-principle demonstration of five-photon entanglement and open-destination teleportation. In the experiment, we use two entangled photon pairs to generate a four-photon entangled state, which is then combined with a single photon state to achieve the experimental goals. The methods developed in our experiment would

We report an experimental realization of entanglement concentration using two polarizationentangled photon pairs produced by pulsed parametric down-conversion. In the meantime, our setup also provides a proof-in-principle demonstration of a quantum repeater. The quality of our procedure is verified by observing a violation of Bell's inequality by more than 5 standard deviations. The high experimental accuracy achieved in the experiment implies that the requirement of tolerable error rate in multi-stage realization of quantum repeaters can be fulfilled, hence providing a practical toolbox for quantum communication over large distances.

We report the first experimental violation of local realism by four-photon Greenberger-Horne-Zeilinger (GHZ) entanglement. In the experiment, the nonstatistical GHZ conflicts between quantum mechanics and local realism are confirmed, within the experimental accuracy, by four specific measurements of polarization correlations between four photons. In addition, our experimental results also demonstrate a strong violation of Mermin-Ardehali-Belinskii-Klyshko inequality by 76 standard deviations. Such a violation can only be attributed to genuine four-photon entanglement.

Salinity is one of the most important abiotic stress affecting the world rice production. The cultivation of salinity-tolerant cultivars is the most costeffective and environmentally friendly approach for salinity control. In recent years, CRISPR/Cas9 systems have been widely used for target-site genome editing; however, their application for the improvement of elite rice cultivars has rarely been reported. Here, we report the improvement of the rice salinity tolerance by engineering a Cas9-OsRR22-gRNA expressing vector, targeting the OsRR22 gene in rice. Nine mutant plants were identified from 14 T 0 transgenic plants. Sequencing showed that these plants had six mutation types at the target site, all of which were successfully transmitted to the next generations. Mutant plants without transferred DNA (T-DNA) were obtained via segregation in the T1 generations. Two T2 homozygous mutant lines were further examined for their salinity tolerance and agronomic traits. The results showed that, at the seedling stage, the salinity tolerance of T2 homozygous mutant lines was significantly enhanced compared to wild-type plants. Furthermore, no significantly different agronomic traits were found between T2 homozygous mutant lines and wild-type plants. Our results indicate CRISPR/ Cas9 as a useful approach to enhance the salinity tolerance of rice.

Universal logic gates for two quantum bits (qubits) form an essential ingredient of quantum information processing. However, the photons, one of the best candidates for qubits, suffer from the lack of strong nonlinear coupling required for quantum logic operations. Here we show how this drawback can be overcome by reporting a proof-of-principle experimental demonstration of a non-destructive controlled-NOT (CNOT) gate for two independent photons using only linear optical elements in conjunction with single-photon sources and conditional dynamics. Moreover, we have exploited the CNOT gate to discriminate all the four Bell-states in a teleportation experiment. The controlled-NOT (CNOT) or similar logic operations between two individual quantum bits (qubits) are essential for various quantum information protocols such as quantum communication [1,2,3] and quantum computation [4]. In recent years, certain quantum logic gates have been experimentally demonstrated, for example, in ion-traps [5,6] and high-finesse microwave cavities [7]. These achievements open many possibilities for future quantum information processing (QIP) with single atoms. Another promising system for QIP is to use single photons. This is due to the photonic robustness against decoherence and the availability of single-qubit operation. However, it has been very difficult to achieve the necessary logic operations for two individual photonqubits since the physical interaction between photons is much too small. Surprisingly, Knill, Laflamme and Milburn (KLM) has shown that nondeterministic quantum logic operations can be performed using linear optical elements, additional photons (ancilla) and postselection based on the output of single-photon detectors [8]. The original proposal by KLM, though elegant, is not economical in its use of optical components. Various schemes have been proposed to reduce the complexity of the KLM scheme while improve its theoretical efficiency [9, 10, 11]. Remarkably, a recent scheme proposed by Nielsen [12] suggests that without using the elaborate teleportation and Z-measurement error correction in the KLM scheme, any non-trivial linear optical gate that succeeds with finite probability is sufficient to obtain efficient quantum computation. Hence, this scheme significantly simplifies the experimental implementation of linear optical quantum computation (LOQC) A crucial requirement in the schemes of LOQC is the so-called classical feedforwardability, that is, it must be in principle possible to detect when the gate has succeeded by performing some appropriate measurement on ancilla photons [8,12]. This information can then be feedfor- . Conditioned on detecting a |− photon in mode 3 ′ and a |H photon in mode 4 ′ one can implement the CNOT operation between the photons 2 and 5. (b) Quantum circuit for quantum teleportation based on a CNOT gate [17]. By using the CNOT operation, Alice can discriminate the four orthogonal Bell state simultaneously such that a complete teleportation can be achieved.ward for conditional futu...

Quantum secret sharing (QSS) and third-man quantum cryptography (TQC) are essential for advanced quantum communication; however, the low intensity and fragility of the multiphoton entanglement source in previous experiments have made their realization an extreme experimental challenge. Here, we develop and exploit an ultrastable high intensity source of four-photon entanglement to report an experimental realization of QSS and TQC. The technology developed in our experiment will be important for future multiparty quantum communication.

Background Nuclear Factor Y (NF-Y) is a heterotrimeric complex composed of three unique subunits: NF-YA, NF-YB, and NF-YC. The NF-Y transcription factor complex binds to the CCAAT box of eukaryotic promoters, playing a vital role in various biological processes in plants. However, the NF-Y gene family has not yet been reported from the peach genome. The current study identified and classified candidate peach NF-Y genes for further functional analysis of this family. Results The current study identified 24 Nuclear Factor Y (NF-Y) transcription factor subunits (6 NF-YA, 12 NF-YB, and 6 NF-YC subunits) in peach. These NF-Y subunits were described with respect to basic physicochemical characteristics, chromosome locations, gene structures, and conserved domains. Based on an analysis of the phylogenetic relationships among peach NF-Ys , six pairs of paralogous NF-Ys were detected. The expansion of the peach NF-Y family occurred by segmental and tandem duplication. Phylogenetic gene synteny of NF-Y proteins was observed between peach and Arabidopsis , and five pairs of paralogous NF-Y proteins from peach and Arabidopsis were identified. Twenty-four peach NF-Y s displayed a diversity of tissue expression patterns. In addition, drought-responsive cis -elements were observed in peach NF-Y promoters, and 9 peach NF-Y genes were shown to distinctly increase their transcript abundances under drought stress. Conclusions This study identified 24 NF-Y genes in the peach genome and analysed their properties at different levels, providing a foundation for researchers to understand this gene family in peach. The up-regulation of 9 NF-Y genes under drought stress indicates that they can serve as candidate functional genes to further study drought resistance in peach. Electronic supplementary material The online version of this article (10.1186/s12864-019-5968-7) contains supplementary material, which is available to authorized users.

Cluster states serve as the central physical resource for the measurement-based quantum computation. We here present a simple experimental demonstration of the scalable cluster-state-construction scheme proposed by Browne and Rudolph. In our experiment, three-photon cluster states are created from two Bell states using linear optical devices. By observing a violation of three-particle Mermin inequality of | A | = 3.10 ± 0.03, we also for the first time report a genuine three-photon entanglement. In addition, the entanglement properties of the cluster states are examined under σz and σx measurements on a qubit.