Journals >Chinese Journal of Quantum Electronics
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2012
Volume: 29 Issue 4
22 Article(s)
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Research Article
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Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 1 (2012)
Interband optical transitions due to ionized acceptor bound excitons in wurtzite GaN strained cylindrical quantum dot
Dong-mei ZHENG, and Zong-chi WANG
Considering the strong built-in electric field(BEF) in the wurtzite cylindrical GaN quantum dot(QD) with finite potential barriers, the interband optical transitions due to the exciton bound by an ion with charge －e (called ionized acceptor bound exciton (A-, X)) are investigated theoretically by means of the variationConsidering the strong built-in electric field(BEF) in the wurtzite cylindrical GaN quantum dot(QD) with finite potential barriers, the interband optical transitions due to the exciton bound by an ion with charge －e (called ionized acceptor bound exciton (A-, X)) are investigated theoretically by means of the variational method. Numerical results show that the emission wavelengths sensitively depend on the QD size(L and R), the position of the ionized acceptor and Al composition x of the barrier material Alx Ga1-x N. The transition wavelength increases if the QD height, QD radius and Al composition x are increased. The emission wavelength firstly increases when the ionized accptor is moved from the left barrier of the QD to right along z-direction, and reaches its maximum when the acceptor is in the vicinity of the left interface of QD. Then the transition wavelength decreases if the acceptor is continuously moved toward right. The minimum value of the transition wavelength can be obtained when the acceptor is in the vicinity of the right interface of QD. The wavelength increases again if the acceptor is further moved to the right barrier of QD. The emission wavelength increases when the acceptor position ρ0 goes from the center of QD. Comparing with the free exciton state without the acceptor, the emission wavelength increases with introducing the ionized acceptor impurity into the left side of the QD center, and the emission wavelength reduces with introducing the ionized acceptor impurity into the right side of the QD center..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 385 (2012)
Framework of entire image chains simulation for optical remote sensing images system
Xiao-shan MA, Xin MENG, Zhen YANG, Xiao-dong PENG, and Wen-ming XIE
The entire image chains simulation for the optical remote sensing images system is still at the starting stage in China. By analyzing the interactions between the atmosphere, the scene and remote sensor, imaging process is divided into three parts: the construction and organization of 3D scene, the simulation of the atThe entire image chains simulation for the optical remote sensing images system is still at the starting stage in China. By analyzing the interactions between the atmosphere, the scene and remote sensor, imaging process is divided into three parts: the construction and organization of 3D scene, the simulation of the at-sensor radiance images and simulation of the sensor effects. The functions of each module and conceptual data flow among these modules are analyzed briefly. At last, the effects of terrain fluctuations and the view zenith angle on imaging are discussed. The results show that with the increase in pixels height from 0 to 1 km, the relative errors of the radiance at-sensor can reach 170%. And the maximum relative error of the radiance at-sensor is close to 50% with the change of the view zenith angles from 180° to 124.4°..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 392 (2012)
Investigation on magnetron cavity used in rubidium atomic frequency standards
Shi-yu YANG, Yao-ting LIANG, Jian-hui TU, and Jing-zhong CUI
The magnetron cavity was developed for use in the rubidium atomic frequency standards, through which the main characteristics of the magnetron cavity were studied, mainly including the resonant frequency, quality factor, oscillation mode. The results show that the resonant frequency of the magnetron cavity can be attenThe magnetron cavity was developed for use in the rubidium atomic frequency standards, through which the main characteristics of the magnetron cavity were studied, mainly including the resonant frequency, quality factor, oscillation mode. The results show that the resonant frequency of the magnetron cavity can be attenuated to 6.835 GHz, which is the resonant frequency for rubidium atoms, and Q-factor can be attenuated to 600～1000, the oscillation mode is typical TE011 mode which is needed for the rubidium atomic frequency standard, and the cavity has a lower frequency temperature coefficient (32.5～35.0 kHz/℃), therefore these derivative magnetron cavities can meet the requirements for rubidium atomic frequency standards well..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 400 (2012)
Motion and fractional angular momentum of charged particle in two-dimensional central-scalar-potential and magnetic flux gauge field
Jun-li XIN
From both classical and quantum aspects, the classical orbits and wave functions of a charged particle motion are investigated in two-dimensional central-scalar-potential as well as the gauge field of a magnetic flux multi-connected space. The result shows that the spatial patterns of the probability clouds of wave funFrom both classical and quantum aspects, the classical orbits and wave functions of a charged particle motion are investigated in two-dimensional central-scalar-potential as well as the gauge field of a magnetic flux multi-connected space. The result shows that the spatial patterns of the probability clouds of wave functions are in excellent agreement with classical orbits. Moreover, fractional quantization rule of angular momentum may be uniquely determined by quantum-classical correspondence. The gauge potential of a magnetic flux cannot change the quantization rule but results in a common topological phase for all wave functions in the given model..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 406 (2012)
Symmetry reductions and explicit solutions of (2+1)-dimensional nonlinear evolution equation
Ying-yuan ZHANG, Xi-qiang LIU, and Gang-wei WANG
Using the compatibility method, symmetry of the nonlinear evolution equation was obtained. By solving the corresponding characteristic equations associated with symmetry equations, symmetry reductions of the (2+1)-dimensional nonlinear evolution equation were given first, then some special type of new explicit solutionUsing the compatibility method, symmetry of the nonlinear evolution equation was obtained. By solving the corresponding characteristic equations associated with symmetry equations, symmetry reductions of the (2+1)-dimensional nonlinear evolution equation were given first, then some special type of new explicit solutions were presented..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 411 (2012)
Homoclinic breather-wave solutions, periodic-wave solutions and kink solitary-wave solutions for CDGKS equations
Ling WANG, and Da-quan XIAN
The homoclinic breather-wave solutions, periodic wave solutions and kink solitary wave solutions of the Caudrey-Dodd-Gibbon-Kotera-Sawada (CDGKS) equation are obtained by combining Painlevé expansion method and extended homoclinic test approach, which enriches the contents and dynamical characteristics of solutionThe homoclinic breather-wave solutions, periodic wave solutions and kink solitary wave solutions of the Caudrey-Dodd-Gibbon-Kotera-Sawada (CDGKS) equation are obtained by combining Painlevé expansion method and extended homoclinic test approach, which enriches the contents and dynamical characteristics of solution..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 417 (2012)
Quantum secret sharing of single-qubit state via tripartite entangled states
Qun-yong ZHANG
Two schemes for quantum secret sharing of single-qubit state were proposed. A symmetric three-qubit entangled state and an asymmetric three-qubit entangled state were used as quantum channel, respectively. The sender performs Bell-basis measurements on her particles, and the cooperator operates single-particle measuremTwo schemes for quantum secret sharing of single-qubit state were proposed. A symmetric three-qubit entangled state and an asymmetric three-qubit entangled state were used as quantum channel, respectively. The sender performs Bell-basis measurements on her particles, and the cooperator operates single-particle measurements on his particles, then the state receiver can reconstruct the original state by applying the appropriate unitary operation. The schemes can also be generalized to the case of arbitrary two-qubit and multi-particle entangled state. The security against certain eavesdropping attacks is also considered. These protocols are considered to be secure..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 421 (2012)
Calculation and analysis of probability and corresponding entropy of Heisenberg model
Wen-juan HAN, Xun ZHOU, and Tai-rong ZHANG
In the situation of ［N,n］ (N is the total number of sites of Heisenberg chain, n is the number of electrons at site spin down) of Heisenberg model, the acquisition probability of eigenvalues and corresponding information entropy definited by Shannon are showed firstly, then the finding probability of site electron spinIn the situation of ［N,n］ (N is the total number of sites of Heisenberg chain, n is the number of electrons at site spin down) of Heisenberg model, the acquisition probability of eigenvalues and corresponding information entropy definited by Shannon are showed firstly, then the finding probability of site electron spin down, the von Neumann of each particle and average von Neumann entropy of the model system (They can embody the relevancy extent of model system) are discussed. The studying results are the following. 1) When the probability of event occurrence is more (less) than 50%, the information entropy decreases (increases) along with the increase of the probability. 2) When n (N) is same and N (n) increases, the acquisition probability of the eigenvalues of ［N,n］ decreases. The corresponding information entropy correctly reflects the obtaining difficulty of the eigenvalue. When n (N) is same, N (n) increases and the parameter is fixed, the finding probability of site electron spin down, the von Neumann entropy of each particle and average von Neumann entropy of the model system decrease(increase) respectively. 3) When ［N,n］ is same, the von Neumann entropy of each particle and average von Neumann entropy of the model system change along with the change of the parameter, the points of inflection arise. These can embody the information of the quantum phase transition of the system. 4) When ［N,n］ and the parameter are same, the von Neumann entropy of the particles of symmetric position of Heisenberg chain is same..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 427 (2012)
Effect of different inhomogeneous magnetic fields on thermal entanglement in a two-qutrit Heisenberg XYZ chain
Meng QIN, Yan-biao LI, and Zhong BAI
The quantum entanglement of two-qutrit Heisenberg XYZ chains interacting with different inhomogeneous magnetic fields is investigated by means of negativity. It is found that the quantum phase transition occurs when the system is in the ground state. The behaviors of entanglement in ferromagnetic and anti-ferromagneticThe quantum entanglement of two-qutrit Heisenberg XYZ chains interacting with different inhomogeneous magnetic fields is investigated by means of negativity. It is found that the quantum phase transition occurs when the system is in the ground state. The behaviors of entanglement in ferromagnetic and anti-ferromagnetic are totally different. So, entanglement can be produced by this feature. It’s also found that the entanglement behaves oscillator when the external magnetic field becomes inhomogeneous. And the x and y component magnetic fields can induce the entanglement to disappear and then to revive. The dependence of the entanglement on parameters varies with different magnetic fields. The entanglement can be controlled by adjusting the directions of external magnetic field and the anisotropy couplings Jz..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 434 (2012)
Influence of Stark shift on entropy and entanglement in J-C model with mixed states
Yao-hua HU
A two-level atom coupling with a single-mode thermal field through two-photon processes is considered. The reduced entropy change of the atom and field was studied by using quantum reduced entropy, and entanglement between the atom and field was measured by using concurrence. By means of numerical computation method, tA two-level atom coupling with a single-mode thermal field through two-photon processes is considered. The reduced entropy change of the atom and field was studied by using quantum reduced entropy, and entanglement between the atom and field was measured by using concurrence. By means of numerical computation method, the effect of the Stark shift and mean photon number in J-C model with mixed states on the reduced entropy change and entanglement was investigated. The results show that reduced entropy changes of the atom and field decrease under the influence of Stark shift. When the initial parameters are suitable, the complete exchange between the atomic and field reduced entropy occurs. In addition, the minimum values of the entanglement raise in the presence of Stark shift, which means that the atom is no longer disentangled from the field..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 441 (2012)
Entanglement of Heisenberg XY model on inhomogeneous periodic chain
Ming CHENG, and Shi-qun ZHU
The time evolution of entanglement and thermal entanglement of an isotropic XY model on the inhomogeneous chain is investigated when there is anisotropic magnetic field. Since entanglement is a very important resource in the field of quantum information, the study of measure and time evolution of entanglement is necessThe time evolution of entanglement and thermal entanglement of an isotropic XY model on the inhomogeneous chain is investigated when there is anisotropic magnetic field. Since entanglement is a very important resource in the field of quantum information, the study of measure and time evolution of entanglement is necessary. The quantity of concurrence was theoretically calculated and it was analyzed by numerical simulations. If the external magnetic field is small and the nearest neighbor coupling is large, the concurrence oscillates between zero and one. If the external magnetic field is large and the nearest neighbor coupling is small, the maximum concurrence can be reduced and even disappears. Meanwhile, the entanglement decreases when the number of spins in the Heisenberg chain increases. The thermal entanglement drops quickly when the temperature increases. It decreases also as the external magnetic field increases. It increases if the inhomogeneity of the system increases..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 448 (2012)
Identification of parameters with different magnitude orders in chaotic Josephson junction by using scale conversion and adaptive synchronization
Fan LI, Long HUANG, Chun-ni WANG, and Jun MA
Josephson junction is an important superconducting device, values of the critical parameters within the Josephson junction model are mapped with different orders of magnitude. As a result, the unknown parameters with smaller order of magnitude can not be detected with high precision by using the original scheme of adapJosephson junction is an important superconducting device, values of the critical parameters within the Josephson junction model are mapped with different orders of magnitude. As a result, the unknown parameters with smaller order of magnitude can not be detected with high precision by using the original scheme of adaptive synchronization. Based on the Lyapunov stability theory, appropriate controller and parameter observers with gain coefficients are approached analytically, a scheme of scale conversion is proposed to estimate the unknown parameters with different orders of magnitude. By defining the statistical error function, the areas of synchronization and non-synchronization are demarcated. It is found that the area of synchronization becomes larger when two smaller unknown parameters are amplified simultaneously. In this way, precision of the identified results is increased greatly, and the results confirm that the scheme is successful to identify the unknown parameters with small order of magnitude..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 457 (2012)
Population number evolution of entangled atoms in multiphoton anti-Jaynes-Cummings model
Muqier , Sachuerfu , and Dong-xia ZHANG
When single mode coherent light field interacts with two identical entangled two-level atoms, the population number evolution of entangled atoms is studied by means of the multi-photon anti-Jaynes-Cummings model. Influence of average photon number of the coherent light field and transition photon number on the populatiWhen single mode coherent light field interacts with two identical entangled two-level atoms, the population number evolution of entangled atoms is studied by means of the multi-photon anti-Jaynes-Cummings model. Influence of average photon number of the coherent light field and transition photon number on the population number evolution of entangled atoms was discussed. The result indicates that the probability difference of the excited state and ground state of the entangled two-level atoms will decrease and whole of oscillation curves of the population number will rise with increasing of average photon number of coherent light field. With the increasing of the transition photon number, the probability difference of the excited state and ground state of the entangled two-level atoms will increase and whole of the oscillation curves of the population number will descend..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 467 (2012)
Density matrix of the harmonic oscillator in thermostat based on coordinate-momentum intermediate representation
Xian-cai WANG
The density matrix of the harmonic oscillator in thermostat is calculated by virtue of the coherent states method and coordinate-momentum intermediate representation. The density matrix of the harmonic oscillator in thermostat is presented only through choosing different parameter values without making use of Fourier-tThe density matrix of the harmonic oscillator in thermostat is calculated by virtue of the coherent states method and coordinate-momentum intermediate representation. The density matrix of the harmonic oscillator in thermostat is presented only through choosing different parameter values without making use of Fourier-transformation relations and direct calculation. Furthermore, the direct way to calculate the density matrix is also shown and the corresponding result is closely related to Hermite polynomials. As a useful application of the above conclusions, a fully new relation on Hermite polynomials can be revealed by comparing both of the above equivalent results..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 472 (2012)
Localization properties of optical waves through three dimensional photonic crystals
Qing-jun XU
Based on the Mie scattering theory and low density approximation, the photonic localization of opal photonic crystal constituted by Ge was studied. The influence laws between the incident wavelength, size of the scatterer, refractive index of medium and localization parameters were numerically revealed. The results shoBased on the Mie scattering theory and low density approximation, the photonic localization of opal photonic crystal constituted by Ge was studied. The influence laws between the incident wavelength, size of the scatterer, refractive index of medium and localization parameters were numerically revealed. The results show that the ideal photonic localization phenomenon appears in middle infrared band (3～12μm) under the conditions of the scatterer density of 10% and the relative refractive index greater than 3.8. With the increase of incident wavelength, the localization area shifts to greater scatterer’s radius, and the localization parameter decreases. Meanwhile, with the increase of medium’s refractive index, the localization phenomena become weak..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 476 (2012)
Compensation and correction of spectrum of chirped super-Gaussian pulse semiconductor lasers
Ke LI, Zhen-hong YU, Lei GAO, and Guo-qiang DAI
Compensation and correction of spectrum of picosecond chirped super-Gaussian pulses generated by semiconductor lasers using a dispersion-shifted fiber (DSF) were achieved. Appropriate spectral compression can reduce inter-symbol interference and prevent the signal distortion induced by excessive spectral stretching, thCompensation and correction of spectrum of picosecond chirped super-Gaussian pulses generated by semiconductor lasers using a dispersion-shifted fiber (DSF) were achieved. Appropriate spectral compression can reduce inter-symbol interference and prevent the signal distortion induced by excessive spectral stretching, thus facilitating steady propagation of super-Gaussian pulses to a certain extent and increasing propagation distance of optical fiber system. The spectral evolution of the super-Gaussian pulse was simulated numerically by symmetrical split-step Fourier method (SSFM) with initial chip of －3, pulse width of 10 ps and peak power of 30 W in the DSF. The results show that the DSF with length of 0.5 m can greatly eliminate “red shift” chirps of the initial pulse..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 481 (2012)
Investigation on effects of substitution position of coumarin on the second-order nonlinear optical properties by DFT method
Xiao-rui LIANG, Gang WANG, Yan-lan JIANG, and Bo ZHAO
The density functional theory (DFT) B3LYP method based on the 6-31G level was employed to optimize the geometric structures of six amino coumarin derivatives. On the basis of obtaining stable molecular configuration, combined with time-dependent density functional theory (TD-DFT), the static second-order nonlinear optiThe density functional theory (DFT) B3LYP method based on the 6-31G level was employed to optimize the geometric structures of six amino coumarin derivatives. On the basis of obtaining stable molecular configuration, combined with time-dependent density functional theory (TD-DFT), the static second-order nonlinear optic polarizabilities (β) and the molecular electric spectrum were calculated by the same method. The results indicated that when amino substitute at the fourth position of coumarin the carbonyl show electron donating property which is a disadvantage for intramolecular charge transfer. When amino substitute at the third, fifth, sixth, seventh and eighth position of coumarin the carbonyl show electron with drawing property which makes the molecule form D-π-A configuration. And the third and seventh position can expand the conjugate system of molecule which can increase the βtot value of coumarin effectively..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 485 (2012)
Density states properties of photonic crystal with group III-V semiconductor material
Shi-qin CHEN
Density states properties of two-dimension square lattice photonic crystals with III-V AlP, AlAs, AlSb and GaP semiconductor material were calculated by plane wave expansion method (PWM). The results showed that they have wide photonic band gaps. The width of band gap increases gradually with the increasing of permittiDensity states properties of two-dimension square lattice photonic crystals with III-V AlP, AlAs, AlSb and GaP semiconductor material were calculated by plane wave expansion method (PWM). The results showed that they have wide photonic band gaps. The width of band gap increases gradually with the increasing of permittivity difference and gets the maximum value at f=0.2a in the normalized frequency. The data reveals among these photonic crystals, the one with AlSb has the widest band gap. All these results provide theoretic basis for the photonic crystal devices..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 491 (2012)
Temperature effect of polaron in quantum disk
Sarengaowa , and Cui-lan ZHAO
Under the condition of electron-LO-phonon strong coupling, the eigen-energy and corresponding eigen-wave functions of the ground state and first excited state of electron in quantum disk were obtained by solving the energy eigen-equation precisely. The phonon effect and temperature effect were studied by unitary transfUnder the condition of electron-LO-phonon strong coupling, the eigen-energy and corresponding eigen-wave functions of the ground state and first excited state of electron in quantum disk were obtained by solving the energy eigen-equation precisely. The phonon effect and temperature effect were studied by unitary transformation and elementary excitation theory method. Furthermore, the temperature effect on the ground energy of the polaron in quantum disk was also discussed. Numerical results showed that few phonons were excited at low temperature, while in the condition of high temperature, the energy of polaron was effected by temperature, and the higher temperature, the more phonons. The results also indicated that the energy of the ground state of polaron decreased with the increasing electron-LO phonon coupling strength. It means that quantum disk has obvious quantum size effect..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 495 (2012)
Performance analysis of two types of chaotic optical secure communication schemes
Pei-yang LIU, Qing-chun ZHAO, and Hong-xi YIN
High dimensional, broadband chaotic optical signal can be generated by a semiconductor laser with external disturbance, which is an ideal carrier for high-speed secure communications. The performances of chaotic optical secure communication systems are numerically studied by encrypting the message by chaos modulation (High dimensional, broadband chaotic optical signal can be generated by a semiconductor laser with external disturbance, which is an ideal carrier for high-speed secure communications. The performances of chaotic optical secure communication systems are numerically studied by encrypting the message by chaos modulation (CMO) or chaos masking (CMS). The variation of the signal-to-noise ratio (SNR) and Q-factor are demonstrated when sinusoidal and digital messages are transmitted separately by CMO or CMS. The correlation coefficient as a function of modulation depth (MD) is discussed. The results show that the system performance varies for different MD or modulation frequency/rate and the performance of CMO system is better than that of CMS..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 500 (2012)
A fiber Bragg grating interrogating dynamic strains sensor system based on interference of polarized mode
Wen-liang HAO, Sheng-lai ZHEN, Zhi-gang CAO, Liang LU, Jun PENG, and Ben-li YU
A simple novel fiber Bragg grating interrogating system is proposed and experimentally demonstrated based on interference of polarized mode. The essential part of the system is only comprised of a high birefringence fiber with fiber reflector and a fiber polarizer. The vibration micro-nano signals from 0.1 Hz to 7.9 kHA simple novel fiber Bragg grating interrogating system is proposed and experimentally demonstrated based on interference of polarized mode. The essential part of the system is only comprised of a high birefringence fiber with fiber reflector and a fiber polarizer. The vibration micro-nano signals from 0.1 Hz to 7.9 kHz were picked up with fidelity. Measurements of dynamic strains with resolutions of 0.5nε/Hz were demonstrated. The results show that the system is suitable for wide frequency range, micro-nano range of dynamic strain detection. This system potentially offers a low-cost and high-performance solution for the interrogation of FBG sensor..
Chinese Journal of Quantum Electronics
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 4, 507 (2012)
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