China’s Contemporary Trends of Trade in Educational Services and It’s Countermeasures under the Opening Environment

While China is opening its educational market to the outside world, the main international trends of trade in educational services are: the developed countries are still the chief exporters while the developing countries are increasing their involvement; aside from the overseas consumption there is also remarkable development in other forms of educational service trade. This text analyzes the main trends of China’s educational service trade under the opening environment, which include: there is a progressively increasing population of overseas students; the number of overseas students whose schooling is paid by themselves is increasing, so is the returning rate; China becomes more and more attractive to foreign students by its unique advantages; Educational mid-organizations have been developing rapidly and other forms of educational service trade have also been experiencing a considerable development. To deal with these trends, we may take several measures as follows under the opening environment: to carry out researches into the law of development of trade in educational services; to standardize the domestic intermediary market; to prefect relevant laws and regulations. Key words: trade in educational services/educational service trade, trend, countermeasure Résumé: Lors de l’ouverture du marché éducatif de la Chine vers l’extérieur, les tendances principales du secteur de service éducatif sont : les pays développés restent encore les exportateurs essentiels alors que les pays en développement augmentent leur part. En plus de la consommation étrangère il y a encore un développement remarquable sous d’autres formes du service éduatif. Cet article analyse les principales tendances du secteur de service éducatif de la Chine dans un environnement ouvert, qui englobent : la population des étudiants étrangers s’agrandit progressivement ; le nombre des étudiants étrangers dont la scolarité est à leur charge augmente, d’où le taux de retour ; la Chine devient de plus en plus attractive pour les étudants étrangers grâce à ses avantages uniques ; les intermédiaires éducatifs se développent rapidement et d’autres formes du service éducatif connaissent aussi un développement considérable. Face à ces tendances, on peut prendre dans un environnement ouvert des mesures comme suite : effectuer des recherches sur la loi de développement sectoriel du service éducatif, standardiser le marché intermédiaire domestique, perfectionner les lois et régulations concernées. Mots-Clés: secteur du service éducatif, tendance, contre-mesur

Implementation of three-qubit Toffoli gate in a single step

Single-step implementations of multi-qubit gates are generally believed to provide a simpler design, a faster operation, and a lower decoherence. For coupled three qubits interacting with a photon field, a realizable scheme for a single-step Toffoli gate is investigated. We find that the three qubit system can be described by four effective modified Jaynes-Cummings models in the states of two control qubits. Within the rotating wave approximation, the modified Jaynes-Cummings models are shown to be reduced to the conventional Jaynes-Cummings models with renormalized couplings between qubits and photon fields. A single-step Toffoli gate is shown to be realizable with tuning the four characteristic oscillation periods that satisfy a commensurate condition. Possible values of system parameters are estimated for single-step Toffli gate. From numerical calculation, further, our single-step Toffoli gate operation errors are discussed due to imperfections in system parameters, which shows that a Toffoli gate with high fidelity can be obtained by adjusting pairs of the photon-qubit and the qubit-qubit coupling strengthes. In addition, a decoherence effect on the Toffoli gate operation is discussed due to a thermal reservoir.Comment: 8 pages, 4 figures, to appear in PR

Topologically nontrivial and trivial zero modes in chiral molecules

Recently, electron transport along chiral molecules has been attracting extensive interest and several intriguing phenomena have been reported in recent experiments, such as the emergence of zero-bias conductance peaks upon the adsorption of single-helical protein on superconducting films. Here, we study theoretically the electron transport through a two-terminal single-helical protein sandwiched between a superconducting electrode and a normal-metal one in the presence of a perpendicular magnetic field. As the proximity-induced superconductivity attenuates with the distance from superconducting media, the pairing potential along the helix axis of the single-helical protein is expected to decrease exponentially, which is characterized by the decay exponent $\lambda$ and closely related to the experiments. Our results indicate that (i) a zero-bias conductance peak of $2e^2/h$ appears at zero temperature and the peak height (width) decreases (broadens) with increasing temperature, and (ii) this zero-bias peak can split into two peaks, which are in agreement with the experiments [see, e.g., Nano Lett. 19, 5167 (2019)]. Remarkably, Majorana zero modes are observed in this protein-superconductor setup in a wide range of model parameters, as manifested by the $Z_2$ topological invariant and the Majoroana oscillation. Interestingly, a specific region is demonstrated for decaying superconductivity, where topologically nontrivial and trivial zero modes coexist and the bandgap remains constant. With increasing the pairing potential, the topologically nontrivial zero modes will transform to the trivial ones without any bandgap closing-reopening, and the critical pairing potential of the phase transition attenuates exponentially with $\lambda$. Additionally, one of the two zero modes can be continuously shifted from one end of the protein toward the other end contacted by the normal-metal electrode.Comment: 11 pages, 6 figure