From a theoretical point of view, Thucydides' s Trap is the idea of realism, especially the idea of offensive realism, that changes in the international power structure will inevitably escalate to international co...From a theoretical point of view, Thucydides' s Trap is the idea of realism, especially the idea of offensive realism, that changes in the international power structure will inevitably escalate to international conflict and war. As we analyze the historical origin of Thucydides' s Trap from the perspective of political strategy, we can see that Thucydides' s Trap was put forward by Graham T. Allison and other western scholars,and that their understanding and analogy between Athens and Sparta,between China and the United States mainly involves three aspects:strength determinism, war benefit theory and bilateral relations theory.These three misunderstandings involve objective factors, subjective factors, and the scope of Thucydides' s Trap. China should avoid falling into the theoretical trap of strength determinism, with great initiative to promote the sustainable development and the rise of China by adhering to the strategy of Chinese Economic Reform and Opening up, and to construct the community of common destiny, while controlling and managing a third-party factor emerging in the Sino-US bilateral relations.展开更多
We investigate the spectra of the electric quadrupole 42^S1/2→3^2D5/2 transitions in a single 40^Ca＋ ion confined in a home-built linear trap. We probe the transitions with an ultra-narrow bandwidth laser at 729nm. ...We investigate the spectra of the electric quadrupole 42^S1/2→3^2D5/2 transitions in a single 40^Ca＋ ion confined in a home-built linear trap. We probe the transitions with an ultra-narrow bandwidth laser at 729nm. In a weak magnetic field, the quadrupole transition splits into ten components with the maximal line strength proportional to their squared Clebsch-Gordan factors. In a magnetic field of the order of Gauss, the observed equidistant sideband reflects the Zeeman substructure modulated by the quantized oscillation due to the secular motion in the trap. The temperature of the trapped ion can be determined by the envelope of the sideband spectrum. We also demonstrate the Rabi oscillation in a carrier transition after the ion has been Doppler cooled, which can be fitted by the model with the thermal state of motion.展开更多
It is widely believed that Shor＇s factoring algorithm provides a driving force to boost the quantum computing research.However, a serious obstacle to its binary implementation is the large number of quantum gates. No...It is widely believed that Shor＇s factoring algorithm provides a driving force to boost the quantum computing research.However, a serious obstacle to its binary implementation is the large number of quantum gates. Non-binary quantum computing is an efficient way to reduce the required number of elemental gates. Here, we propose optimization schemes for Shor＇s algorithm implementation and take a ternary version for factorizing 21 as an example. The optimized factorization is achieved by a two-qutrit quantum circuit, which consists of only two single qutrit gates and one ternary controlled-NOT gate. This two-qutrit quantum circuit is then encoded into the nine lower vibrational states of an ion trapped in a weakly anharmonic potential. Optimal control theory（OCT） is employed to derive the manipulation electric field for transferring the encoded states. The ternary Shor＇s algorithm can be implemented in one single step. Numerical simulation results show that the accuracy of the state transformations is about 0.9919.展开更多
文摘From a theoretical point of view, Thucydides' s Trap is the idea of realism, especially the idea of offensive realism, that changes in the international power structure will inevitably escalate to international conflict and war. As we analyze the historical origin of Thucydides' s Trap from the perspective of political strategy, we can see that Thucydides' s Trap was put forward by Graham T. Allison and other western scholars,and that their understanding and analogy between Athens and Sparta,between China and the United States mainly involves three aspects:strength determinism, war benefit theory and bilateral relations theory.These three misunderstandings involve objective factors, subjective factors, and the scope of Thucydides' s Trap. China should avoid falling into the theoretical trap of strength determinism, with great initiative to promote the sustainable development and the rise of China by adhering to the strategy of Chinese Economic Reform and Opening up, and to construct the community of common destiny, while controlling and managing a third-party factor emerging in the Sino-US bilateral relations.
基金Supported by the National Fundamental Research Program of China under Grant No 2012CB922102the National Natural Science Foundation of China under the Grant Nos 11274352 and 11104325
文摘We investigate the spectra of the electric quadrupole 42^S1/2→3^2D5/2 transitions in a single 40^Ca＋ ion confined in a home-built linear trap. We probe the transitions with an ultra-narrow bandwidth laser at 729nm. In a weak magnetic field, the quadrupole transition splits into ten components with the maximal line strength proportional to their squared Clebsch-Gordan factors. In a magnetic field of the order of Gauss, the observed equidistant sideband reflects the Zeeman substructure modulated by the quantized oscillation due to the secular motion in the trap. The temperature of the trapped ion can be determined by the envelope of the sideband spectrum. We also demonstrate the Rabi oscillation in a carrier transition after the ion has been Doppler cooled, which can be fitted by the model with the thermal state of motion.
基金supported by the National Natural Science Foundation of China(Grant No.61205108)the High Performance Computing(HPC)Foundation of National University of Defense Technology,China
文摘It is widely believed that Shor＇s factoring algorithm provides a driving force to boost the quantum computing research.However, a serious obstacle to its binary implementation is the large number of quantum gates. Non-binary quantum computing is an efficient way to reduce the required number of elemental gates. Here, we propose optimization schemes for Shor＇s algorithm implementation and take a ternary version for factorizing 21 as an example. The optimized factorization is achieved by a two-qutrit quantum circuit, which consists of only two single qutrit gates and one ternary controlled-NOT gate. This two-qutrit quantum circuit is then encoded into the nine lower vibrational states of an ion trapped in a weakly anharmonic potential. Optimal control theory（OCT） is employed to derive the manipulation electric field for transferring the encoded states. The ternary Shor＇s algorithm can be implemented in one single step. Numerical simulation results show that the accuracy of the state transformations is about 0.9919.
