Thework presents the electronic structure computations and optical spectroscopy studies of half-Heusler ScNiBi and YNiBi compounds.Our first-principles computations of the electronic structures were based on density f...Thework presents the electronic structure computations and optical spectroscopy studies of half-Heusler ScNiBi and YNiBi compounds.Our first-principles computations of the electronic structures were based on density functional theory accounting for spin-orbit coupling.These compounds are computed to be semiconductors.The calculated gap values make ScNiBi and YNiBi valid for thermoelectric and optoelectronic applications and as selective filters.In ScNiBi and YNiBi,an intense peak at the energy of−2 eV is composed of theNi 3d states in the conduction band,and the valence band mostly contains these states with some contributions from the Bi 6p and Sc 3d or Y 4d electronic states.These states participate in the formation of the indirect gap of 0.16 eV(ScNiBi)and 0.18 eV(YNiBi).Within the spectral ellipsometry technique in the interval 0.22–15μm of wavelength,the optical functions of materials are studied,and their dispersion features are revealed.A good matching of the experimental and modeled optical conductivity spectra allowed us to analyze orbital contributions.The abnormally low optical absorption observed in the low-energy region of the spectrum is referred to as the results of band calculations indicating a small density of electronic states near the Fermi energy of these complex materials.展开更多
The emphasis on the simplification of cognitive and motor tasks by recent results of morphological computation has rendered possible the construction of appropriate“mimetic bodies”able to render accompanied computat...The emphasis on the simplification of cognitive and motor tasks by recent results of morphological computation has rendered possible the construction of appropriate“mimetic bodies”able to render accompanied computations simpler,according to a general appeal to the“simplexity”of animal embodied cognition.A new activity of what we can call“distributed computation”holds the promise of originating a new generation of robots with better adaptability and restricted number of required control parameters.The framework of distributed computation helps us see them in a more naturalized and prudent perspective,avoiding ontological or metaphysical considerations.Despite these progresses,there are still problems regarding the epistemological limitations of computational modeling remain to be solved.展开更多
We propose an efficient and robust way to design absorbing boundary conditions in atomistic computations. An optimal discrete boundary condition is obtained by minimizing a functional of a reflection coefficient integ...We propose an efficient and robust way to design absorbing boundary conditions in atomistic computations. An optimal discrete boundary condition is obtained by minimizing a functional of a reflection coefficient integral over a range of wave numbers. The minimization is performed with respect to a set of wave numbers, at which transparent absorption is reached. Compared with the optimization with respect to the boundary condition coefficients suggested by E and Huang [Phys. Rev. Lett. 87 （2001） 133501], we reduce considerably the number of independent variables and the computing cost. We further demonstrate with numerical examples that both the optimization and the wave absorption are more robust in the proposed design.展开更多
Physical reservoir computing(PRC)offers an effective computing paradigm for spatiotemporal information processing with low training costs.Achieving controllable regulation over the temporal dynamics of devices to meet...Physical reservoir computing(PRC)offers an effective computing paradigm for spatiotemporal information processing with low training costs.Achieving controllable regulation over the temporal dynamics of devices to meet the computational demands of each physical layer is a key challenge for realizing highperformance PRC chips.Here,we proposed a homogeneously integrated all-PRC with tunable temporal dynamics.Utilizing the modulation effect of oxygen vacancies on the energy barrier of the pentacene/ZnO interface,shortterm memory,and long-term memory switching characteristics have been achieved within the same device structure.Furthermore,by altering the gate voltage,the reservoir exhibited a broad range ratio of temporal characteristics(>10^(2)),which provides the potential to map information with different temporal characteristics.Inspired by the process of encoding and reconstructing spatiotemporal information in the human visual system,a biomimetic obstacle recognition system has been constructed to assist visually impaired individuals in walking,demonstrating excellent accuracy in obstacle types(100%)and distances(97.2%)recognition.This work offers a promising avenue for the development of an integrated PRC system with multi-timescale information processing capability.展开更多
We further study the validity of the Monte Carlo Hamiltonian method. The advantage of the method, in comparison with the standard Monte Carlo Lagrangian approach, is its capability to study the excited states. We cons...We further study the validity of the Monte Carlo Hamiltonian method. The advantage of the method, in comparison with the standard Monte Carlo Lagrangian approach, is its capability to study the excited states. We consider two quantum mechanical models: a symmetric one ; and an asymmetric one , for and , for . The results for the spectrum, wave functions and thermodynamical observables are in agreement with the analytical or Runge–Kutta calculations.展开更多
The Monte Carlo Hamiltonian method developed recently allows to investigate the ground state and low-lying excited states of a quantum system,using Monte Carlo(MC)algorithm with importance sampling.However,conventiona...The Monte Carlo Hamiltonian method developed recently allows to investigate the ground state and low-lying excited states of a quantum system,using Monte Carlo(MC)algorithm with importance sampling.However,conventional MC algorithm has some difficulties when applied to inverse potentials.We propose to use effective potential and extrapolation method to solve the problem.We present examples from the hydrogen system.展开更多
Two 3-D numerical models of the discrete element method （DEM） for impact problems are proposed. The models can calculate not only the impact problems of continuum and non-continuum, but also the transient process fr...Two 3-D numerical models of the discrete element method （DEM） for impact problems are proposed. The models can calculate not only the impact problems of continuum and non-continuum, but also the transient process from continuum to non-continuum. The stress wave propagation in a concrete block and a dynamic splitting process of a marble disc under impact loading are numerically simulated with the proposed models. By comparing the numerical results with the corresponding results obtained by the finite element method （FEM） and the experiments, it is proved that the models are reliable for three-dimensional impact problems.展开更多
Light intensity distribution in the vicinity of inclusions and etched cracks in polished fused silica at wavelength scale are simulated by using the finite-difference time-domain algorithm. Light intensity enhancement...Light intensity distribution in the vicinity of inclusions and etched cracks in polished fused silica at wavelength scale are simulated by using the finite-difference time-domain algorithm. Light intensity enhancement factor as functions of diameter and refractive index of inclusions are investigated, more than 10 times that of incident beam is obtained in the simulation. We model the etched crack in close proximity to a real structure, which is characterized by AFM. We find that the peak light intensity of the crack is a function of its cross sectional breadth depth ratio, providing good hints for the effective processing of fused silica samples to improve the damage threshold.展开更多
The generation of various entangled states is an essential task in quantum information processing. Recently, a scheme （PRA 79, 022304） has been suggested for generating Greenberger-Horne-Zeilinger state and cluster ...The generation of various entangled states is an essential task in quantum information processing. Recently, a scheme （PRA 79, 022304） has been suggested for generating Greenberger-Horne-Zeilinger state and cluster state with atomic ensembles based on the Rydberg blockade. Using similar resources as the earlier scheme, here we propose an experimentally feasible scheme of preparing arbitrary four-qubit W class of maximally and non- maximally entangled states with atomic ensembles in a single step. Moreover, we carefully analyze the realistic noises and predict that four-qubit W states can be produced with high fidelity （F - 0.994） via our scheme.展开更多
A new implementation of high-dimensional quantum key distribution （QKD） protocol is discussed. Using three mutual unbiased bases, we present a d？level six-state QKD protocol that exploits the orbital angular moment...A new implementation of high-dimensional quantum key distribution （QKD） protocol is discussed. Using three mutual unbiased bases, we present a d？level six-state QKD protocol that exploits the orbital angular momentum with the spatial mode of the light beam. The protocol shows that the feature of a high capacity since keys are encoded using photon modes in d-level Hilbert space. The devices for state preparation and measurement are also discussed. This protocol has high security and the alignment of shared reference frames is not needed between sender and receiver.展开更多
Using the method presented recently [Phys.Rev.A 77（2008）014306; Phys.Lett.A 369（2007）377], the transformation operator （TO） is explicitly given for teleporting an arbitrary three-qubit state with a six-qubit cha...Using the method presented recently [Phys.Rev.A 77（2008）014306; Phys.Lett.A 369（2007）377], the transformation operator （TO） is explicitly given for teleporting an arbitrary three-qubit state with a six-qubit channel and Bell-state measurements. A criterion on whether such quantum teleportation can be perfectly realized is educed in terms of TO. Moreover, six instantiations on TO and criterion are concisely shown.展开更多
A linear delayed position feedback control is applied to control the erosion of safe basins in a Holmes-Duffing system. The conditions of fractal erosion of the safe basin of the controlled system on the basis that th...A linear delayed position feedback control is applied to control the erosion of safe basins in a Holmes-Duffing system. The conditions of fractal erosion of the safe basin of the controlled system on the basis that the range of time delay leading to good control is obtained by the Melnikov method. It is found that the increasing time delay can reduce the basin erosion under a weak and positive feedback g^in. Then the evolutions of safe basins with time delay are presented in detail by the fourth Runge-Kutta and Monte-Carlo methods, which shows that the safe basin of the controlled Holmes Dulling system can be expanded, and its fractal can be reduced by the increasing time delay. These results suggest that delayed position feedbacks can be used as a good approach to control the erosion of safe basins.展开更多
An adaptive fast multipole higher order boundary element method combining fast multipole （FM） with a higher order boundary element method is studied to solve the power frequency electric field （PFEF） of substation...An adaptive fast multipole higher order boundary element method combining fast multipole （FM） with a higher order boundary element method is studied to solve the power frequency electric field （PFEF） of substations. In this new technique, the iterative equation solver GMRES is used in the FM, where matrix-vector multiplications are calculated using fast multipole expansions. The coefficients in the preconditioner for GMRES are stored and are used repeatedly in the direct evaluations of the near-field contributions. Then a 500kV outdoor substation is modeled and the PFEF of the substation is analyzed by the novel algorithm and other conventional methods. The results show that, in computational cost and the storages capability aspects, the algorithm proposed in this study has obvious advantages. It is suitable for the calculation of the large-scale PFEF in complex substations and the design of electromagnetic compatibility.展开更多
A protocol is proposed to implement a three-qubit phase gate for photonic qubits in a three-mode cavity. The idea can be extended to directly implement a N-qubit phase gate. We also show that the interaction time rema...A protocol is proposed to implement a three-qubit phase gate for photonic qubits in a three-mode cavity. The idea can be extended to directly implement a N-qubit phase gate. We also show that the interaction time remains unchanged with the increasing number of qubits. In addition, the influence of cavity decay and atomic spontaneous emission on the gate fidelity and photon loss probability is also discussed by numerical calculation.展开更多
Based on the classical time division multi-channel communication theory, we present a scheme of quantum time- division multi-channel communication （QTDMC）. Moreover, the model of quantum time division switch （QTDS...Based on the classical time division multi-channel communication theory, we present a scheme of quantum time- division multi-channel communication （QTDMC）. Moreover, the model of quantum time division switch （QTDS） and correlative protocol of QTDMC are proposed. The quantum bit error rate （QBER） is analyzed and the QBER simulation test is performed. The scheme shows that the QTDS can carry out multi-user communication through quantum channel, the QBER can also reach the reliability requirement of communication, and the protocol of QTDMC has high practicability and transplantable. The scheme of QTDS may play an important role in the establishment of quantum communication in a large scale in the future.展开更多
We propose a simple birefringent terahertz （THz） waveguide which is a polymer elliptical tube with a cross section of elliptical ring structure. It can be achieved by stretching a normal circular-tube in one directi...We propose a simple birefringent terahertz （THz） waveguide which is a polymer elliptical tube with a cross section of elliptical ring structure. It can be achieved by stretching a normal circular-tube in one direction. Simulations based on the full-vector finite element method （FEM） show that this kind of waveguides exhibits high birefringenee on a level of 10- 2 over a wide THz frequency range. Moreover, as a majority of modal power is trapped in the air core inside the polymer elliptical tube, the THz waveguide guiding loss caused by material absorption can be reduced effectively.展开更多
We propose a new two-type-player prisoner＇s dilemma game based on the division of work on a square lattice, in which a fraction of the population μ are assigned type A and the rest B. In a one-shot two-player game, ...We propose a new two-type-player prisoner＇s dilemma game based on the division of work on a square lattice, in which a fraction of the population μ are assigned type A and the rest B. In a one-shot two-player game, we let both of their original payoffs be scaled by a same multiplicative factor α 〉 1, if two neighboring players are of different types; however we leave the payoffs unchanged if they are of the same type. Then we show that combined with the two-type setup, the square lattice can assist to induce different social ranks according to players＇ abilities to collect payoffs. Simulation results show that the density of cooperation is significantly promoted for a wide range of the temptation to defection parameters and that there are optimal values for both α and μ leading to the maximal cooperation level. We reach these results by analyzing the distribution of the players in the social ranks and we also show some typical snapshots of the system.展开更多
The stochastic resonance （SR） in a time-delayed mono-stable system driven by multiplicative white noise, additive white noise, additive dichotomous noise as well as a periodic square-wave signal is considered from t...The stochastic resonance （SR） in a time-delayed mono-stable system driven by multiplicative white noise, additive white noise, additive dichotomous noise as well as a periodic square-wave signal is considered from the view of the signal-to-noise ratio （SNR）. It is found that the SNR increases monotonically with the increase of the delay time. The SNR exhibits the SR behavior when it is plotted as a function of intensities of the noises, displaying the asymmetry of the dichotomous noise. The SNR varies non-monotonically with the increase of the system parameter and the amplitude of the input square-wave signal.展开更多
The phenomenon of entropic stochastic resonance （ESR） in a two-dimensional confined system driven by a transverse periodic force is investigated when the colored fluctuation is included in the system. Applying the m...The phenomenon of entropic stochastic resonance （ESR） in a two-dimensional confined system driven by a transverse periodic force is investigated when the colored fluctuation is included in the system. Applying the method of unified colored noise approximation, the approximate Fokker-Planck equation can be derived in the absence of the periodic force. Through the escaping rate of the Brownian particle from one well to the other, the power spectral amplification can be obtained. It is found that increasing the values of the noise correlation time and the signal frequency can suppress the ESR of the system.展开更多
文摘Thework presents the electronic structure computations and optical spectroscopy studies of half-Heusler ScNiBi and YNiBi compounds.Our first-principles computations of the electronic structures were based on density functional theory accounting for spin-orbit coupling.These compounds are computed to be semiconductors.The calculated gap values make ScNiBi and YNiBi valid for thermoelectric and optoelectronic applications and as selective filters.In ScNiBi and YNiBi,an intense peak at the energy of−2 eV is composed of theNi 3d states in the conduction band,and the valence band mostly contains these states with some contributions from the Bi 6p and Sc 3d or Y 4d electronic states.These states participate in the formation of the indirect gap of 0.16 eV(ScNiBi)and 0.18 eV(YNiBi).Within the spectral ellipsometry technique in the interval 0.22–15μm of wavelength,the optical functions of materials are studied,and their dispersion features are revealed.A good matching of the experimental and modeled optical conductivity spectra allowed us to analyze orbital contributions.The abnormally low optical absorption observed in the low-energy region of the spectrum is referred to as the results of band calculations indicating a small density of electronic states near the Fermi energy of these complex materials.
文摘The emphasis on the simplification of cognitive and motor tasks by recent results of morphological computation has rendered possible the construction of appropriate“mimetic bodies”able to render accompanied computations simpler,according to a general appeal to the“simplexity”of animal embodied cognition.A new activity of what we can call“distributed computation”holds the promise of originating a new generation of robots with better adaptability and restricted number of required control parameters.The framework of distributed computation helps us see them in a more naturalized and prudent perspective,avoiding ontological or metaphysical considerations.Despite these progresses,there are still problems regarding the epistemological limitations of computational modeling remain to be solved.
基金Supported in part by the National Natural Science Foundation of China under Grant No 10872004, the National Basic Research Program of China under Grant No 2007CB814800, and the Ministry of Education of China under Grant Nos NCET-06-0011 and 200800010013.
文摘We propose an efficient and robust way to design absorbing boundary conditions in atomistic computations. An optimal discrete boundary condition is obtained by minimizing a functional of a reflection coefficient integral over a range of wave numbers. The minimization is performed with respect to a set of wave numbers, at which transparent absorption is reached. Compared with the optimization with respect to the boundary condition coefficients suggested by E and Huang [Phys. Rev. Lett. 87 （2001） 133501], we reduce considerably the number of independent variables and the computing cost. We further demonstrate with numerical examples that both the optimization and the wave absorption are more robust in the proposed design.
基金National Key Research and Development Program of China,Grant/Award Number:2021YFA0717900National Natural Science Foundation of China,Grant/Award Numbers:62471251,62288102,22275098,62405144+1 种基金Basic Research Program of Jiangsu,Grant/Award Numbers:BK20240033,BK20243057Jiangsu Funding Program for Excellent Postdoctoral Talent,Grant/Award Number:2022ZB402。
文摘Physical reservoir computing(PRC)offers an effective computing paradigm for spatiotemporal information processing with low training costs.Achieving controllable regulation over the temporal dynamics of devices to meet the computational demands of each physical layer is a key challenge for realizing highperformance PRC chips.Here,we proposed a homogeneously integrated all-PRC with tunable temporal dynamics.Utilizing the modulation effect of oxygen vacancies on the energy barrier of the pentacene/ZnO interface,shortterm memory,and long-term memory switching characteristics have been achieved within the same device structure.Furthermore,by altering the gate voltage,the reservoir exhibited a broad range ratio of temporal characteristics(>10^(2)),which provides the potential to map information with different temporal characteristics.Inspired by the process of encoding and reconstructing spatiotemporal information in the human visual system,a biomimetic obstacle recognition system has been constructed to assist visually impaired individuals in walking,demonstrating excellent accuracy in obstacle types(100%)and distances(97.2%)recognition.This work offers a promising avenue for the development of an integrated PRC system with multi-timescale information processing capability.
文摘We further study the validity of the Monte Carlo Hamiltonian method. The advantage of the method, in comparison with the standard Monte Carlo Lagrangian approach, is its capability to study the excited states. We consider two quantum mechanical models: a symmetric one ; and an asymmetric one , for and , for . The results for the spectrum, wave functions and thermodynamical observables are in agreement with the analytical or Runge–Kutta calculations.
基金国家自然科学基金，Talent Project of the Ministry of Education of China,Science Foundation of Educational Bureau of Guangdong Province of China,the Key Project of International Col，广东省教育厅科研项目，国际合作项目，加拿大国家科学及工程研究基金
文摘The Monte Carlo Hamiltonian method developed recently allows to investigate the ground state and low-lying excited states of a quantum system,using Monte Carlo(MC)algorithm with importance sampling.However,conventional MC algorithm has some difficulties when applied to inverse potentials.We propose to use effective potential and extrapolation method to solve the problem.We present examples from the hydrogen system.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10572002 and 10732010.
文摘Two 3-D numerical models of the discrete element method （DEM） for impact problems are proposed. The models can calculate not only the impact problems of continuum and non-continuum, but also the transient process from continuum to non-continuum. The stress wave propagation in a concrete block and a dynamic splitting process of a marble disc under impact loading are numerically simulated with the proposed models. By comparing the numerical results with the corresponding results obtained by the finite element method （FEM） and the experiments, it is proved that the models are reliable for three-dimensional impact problems.
文摘Light intensity distribution in the vicinity of inclusions and etched cracks in polished fused silica at wavelength scale are simulated by using the finite-difference time-domain algorithm. Light intensity enhancement factor as functions of diameter and refractive index of inclusions are investigated, more than 10 times that of incident beam is obtained in the simulation. We model the etched crack in close proximity to a real structure, which is characterized by AFM. We find that the peak light intensity of the crack is a function of its cross sectional breadth depth ratio, providing good hints for the effective processing of fused silica samples to improve the damage threshold.
基金Supported by the National Natural Science Foundation of China under Grant No 10774192, the Fund of Innovation of Graduate School of National University of Defense Technology under Grant No 080201.
文摘The generation of various entangled states is an essential task in quantum information processing. Recently, a scheme （PRA 79, 022304） has been suggested for generating Greenberger-Horne-Zeilinger state and cluster state with atomic ensembles based on the Rydberg blockade. Using similar resources as the earlier scheme, here we propose an experimentally feasible scheme of preparing arbitrary four-qubit W class of maximally and non- maximally entangled states with atomic ensembles in a single step. Moreover, we carefully analyze the realistic noises and predict that four-qubit W states can be produced with high fidelity （F - 0.994） via our scheme.
基金Supported by the National Basic Research Program of China under Grant Nos 2006CB921106 and 2010CB923202, the Fundamental Research Funds for the Central Universities No BUPT2009RC0710, the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No 20090005120008, and the National Natural Science Foundation of China under Grant No 10947151.
文摘A new implementation of high-dimensional quantum key distribution （QKD） protocol is discussed. Using three mutual unbiased bases, we present a d？level six-state QKD protocol that exploits the orbital angular momentum with the spatial mode of the light beam. The protocol shows that the feature of a high capacity since keys are encoded using photon modes in d-level Hilbert space. The devices for state preparation and measurement are also discussed. This protocol has high security and the alignment of shared reference frames is not needed between sender and receiver.
基金Supported by the New Century Excellent Talent Project （NCET） of the Ministry of Education of China under Grant No NCET-06-0554, the National Natural Science Foundation of China under Grant Nos 10975001, 60677001, 10747146 and 10874122, the Science-Technology Fund of Anhui Province for Outstanding Youth under Grant No 06042087, the Key Fund of the Ministry of Education of China under Grant No 206063, the General Fund of the Educational Committee of Anhui Province under Grant No 2006KJ260B, the Natural Science Foundation of Guangdong Province under Grant Nos 06300345 and 7007806, and the Talent Foundation of High Education of Anhui Province for Outstanding Youth under Grant No 2009SQRZ018.
文摘Using the method presented recently [Phys.Rev.A 77（2008）014306; Phys.Lett.A 369（2007）377], the transformation operator （TO） is explicitly given for teleporting an arbitrary three-qubit state with a six-qubit channel and Bell-state measurements. A criterion on whether such quantum teleportation can be perfectly realized is educed in terms of TO. Moreover, six instantiations on TO and criterion are concisely shown.
基金Supported by the National Natural Science Foundation of China under Grant No 10902071, Shanghai Municipal Education Commission under Grant No YYY08004, Shanghai Leading Academic Discipline Project under Grant No J51501, and Key Project of the National Natural Science Foundation of China under Grant No 11032009
文摘A linear delayed position feedback control is applied to control the erosion of safe basins in a Holmes-Duffing system. The conditions of fractal erosion of the safe basin of the controlled system on the basis that the range of time delay leading to good control is obtained by the Melnikov method. It is found that the increasing time delay can reduce the basin erosion under a weak and positive feedback g^in. Then the evolutions of safe basins with time delay are presented in detail by the fourth Runge-Kutta and Monte-Carlo methods, which shows that the safe basin of the controlled Holmes Dulling system can be expanded, and its fractal can be reduced by the increasing time delay. These results suggest that delayed position feedbacks can be used as a good approach to control the erosion of safe basins.
基金Supported by the National Natural Science Foundations of China under Grant No 50877082, the National Basic Research Program of China under Grant No 2009CB724506, and the Specialized Research Fund for State Key Laboratory of Power Transmission Equipment ＆ System Security and New Technology under Grant No 2007DA10512708304.
文摘An adaptive fast multipole higher order boundary element method combining fast multipole （FM） with a higher order boundary element method is studied to solve the power frequency electric field （PFEF） of substations. In this new technique, the iterative equation solver GMRES is used in the FM, where matrix-vector multiplications are calculated using fast multipole expansions. The coefficients in the preconditioner for GMRES are stored and are used repeatedly in the direct evaluations of the near-field contributions. Then a 500kV outdoor substation is modeled and the PFEF of the substation is analyzed by the novel algorithm and other conventional methods. The results show that, in computational cost and the storages capability aspects, the algorithm proposed in this study has obvious advantages. It is suitable for the calculation of the large-scale PFEF in complex substations and the design of electromagnetic compatibility.
文摘A protocol is proposed to implement a three-qubit phase gate for photonic qubits in a three-mode cavity. The idea can be extended to directly implement a N-qubit phase gate. We also show that the interaction time remains unchanged with the increasing number of qubits. In addition, the influence of cavity decay and atomic spontaneous emission on the gate fidelity and photon loss probability is also discussed by numerical calculation.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61072057 and 60672119, the 111 Project （B08038）, the State Key Lab of Integrated Services Networks （ISN 1001004）, the Fundamental Research Funds for the Central Universities （No K50510010004）, the Natural Science Basic Research Project in Shaanxi Province （2010JM8021）, Young Teacher Research Funds of Xilan Institute of Post and Telecommunication （ZL2010-05）, and Scientific Research Project of the Education Department of Shaanxi （2010JK834）.
文摘Based on the classical time division multi-channel communication theory, we present a scheme of quantum time- division multi-channel communication （QTDMC）. Moreover, the model of quantum time division switch （QTDS） and correlative protocol of QTDMC are proposed. The quantum bit error rate （QBER） is analyzed and the QBER simulation test is performed. The scheme shows that the QTDS can carry out multi-user communication through quantum channel, the QBER can also reach the reliability requirement of communication, and the protocol of QTDMC has high practicability and transplantable. The scheme of QTDS may play an important role in the establishment of quantum communication in a large scale in the future.
文摘We propose a simple birefringent terahertz （THz） waveguide which is a polymer elliptical tube with a cross section of elliptical ring structure. It can be achieved by stretching a normal circular-tube in one direction. Simulations based on the full-vector finite element method （FEM） show that this kind of waveguides exhibits high birefringenee on a level of 10- 2 over a wide THz frequency range. Moreover, as a majority of modal power is trapped in the air core inside the polymer elliptical tube, the THz waveguide guiding loss caused by material absorption can be reduced effectively.
基金Supported by the National Basic Research Program of China under Grant No 2006CB705500, the National Natural Science Foundation of China under Grant Nos 60744003, 10635040 and 10532060, the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No 20060358065, and the National Science Fund for Fostering Talents in Basic Science （J0630319）.
文摘We propose a new two-type-player prisoner＇s dilemma game based on the division of work on a square lattice, in which a fraction of the population μ are assigned type A and the rest B. In a one-shot two-player game, we let both of their original payoffs be scaled by a same multiplicative factor α 〉 1, if two neighboring players are of different types; however we leave the payoffs unchanged if they are of the same type. Then we show that combined with the two-type setup, the square lattice can assist to induce different social ranks according to players＇ abilities to collect payoffs. Simulation results show that the density of cooperation is significantly promoted for a wide range of the temptation to defection parameters and that there are optimal values for both α and μ leading to the maximal cooperation level. We reach these results by analyzing the distribution of the players in the social ranks and we also show some typical snapshots of the system.
文摘The stochastic resonance （SR） in a time-delayed mono-stable system driven by multiplicative white noise, additive white noise, additive dichotomous noise as well as a periodic square-wave signal is considered from the view of the signal-to-noise ratio （SNR）. It is found that the SNR increases monotonically with the increase of the delay time. The SNR exhibits the SR behavior when it is plotted as a function of intensities of the noises, displaying the asymmetry of the dichotomous noise. The SNR varies non-monotonically with the increase of the system parameter and the amplitude of the input square-wave signal.
基金Supported by the National Natural Science Foundation of China under Grant No 10847156.
文摘The phenomenon of entropic stochastic resonance （ESR） in a two-dimensional confined system driven by a transverse periodic force is investigated when the colored fluctuation is included in the system. Applying the method of unified colored noise approximation, the approximate Fokker-Planck equation can be derived in the absence of the periodic force. Through the escaping rate of the Brownian particle from one well to the other, the power spectral amplification can be obtained. It is found that increasing the values of the noise correlation time and the signal frequency can suppress the ESR of the system.
