If a coherent perturbation field is used to couple the excited level of the coupling transition in the five-levelK-type atom with another higher excited level,the two-photon electromagnetically induced transparency ca...If a coherent perturbation field is used to couple the excited level of the coupling transition in the five-levelK-type atom with another higher excited level,the two-photon electromagnetically induced transparency can be locallymodulated by altering the parameters of the additional perturbation field.With different detunings of the coherentperturbation field,the absorption peak or transparency window with sharp and high-contrast spectral feature can begenerated in the two-photon absorption spectrum.The physical interpretation of these phenomena is given in terms ofthe dressed states.展开更多
In this paper we present systematic differential representations for the dynamical group SO(4).Theserepresentations include the left and the right differential representations and the left and the right adjoint differ...In this paper we present systematic differential representations for the dynamical group SO(4).Theserepresentations include the left and the right differential representations and the left and the right adjoint differentialrepresentations in both the group parameter space and its coset spaces.They are the generalization of the differentialrepresentations of the SO(3) rotation group in the Euler angles.These representations may find their applications in thestudy of the physical systems with SO(4) dynamical symmetry.展开更多
We find that in a supersymmetric quantum mechanics (SUSY QM) system,in addition to supersymmetric algebra,an associated SU(2) algebra can be obtained by using semiunitary (SUT) operator and projection operator, and th...We find that in a supersymmetric quantum mechanics (SUSY QM) system,in addition to supersymmetric algebra,an associated SU(2) algebra can be obtained by using semiunitary (SUT) operator and projection operator, and the relevant constants of motion can be constructed.Two typical quantum systems are investigated as examples to demonstrate the above finding.The first example is the quantum system of a nonrelativistic charged particle moving in x-y plane and coupled to a magnetic field along z-axis.The second example is provided with the Dirac particle in a magnetic field.Similarly there exists an SUr(2)(?)SU_σ(2) symmetry in the context of the relativistic Pauli Hamiltonian squared.We show that there exists also an SU(2) symmetry associated with the supersymmetry of the Dirac particle.展开更多
Due to interaction with the vacuum of the radiation field,a K-type atomic system with near-degenerateexcited and ground levels,which is driven by two strong coherent fields and two weak probe fields,has additional coh...Due to interaction with the vacuum of the radiation field,a K-type atomic system with near-degenerateexcited and ground levels,which is driven by two strong coherent fields and two weak probe fields,has additional coherenceterms—the vacuum-induced coherence (VIC) terms.In this paper,we find that,if the interference is optimized,thetwo-photon absorption properties of this atom system can be significantly modified and electromagnetically-inducedtransparency (EIT) is dependent on this interference.Furthermore,we find that in all the cases the coherence can suppressor enhance the partial two-photon transparency,while the complete transparency window is still strictly preserved,whichmeans that it cannot be affected by the VIC.Another important result is the finding of the crucial role played by therelative phase between the probe and coupling fields:the relative height of absorption peaks can be modulated by therelative phase.The physical interpretation of the phenomena has been given.展开更多
Algebraic dynamics is applied to treat Landau system.We consider the case with the vector potential A=B(g)(-y,0,0)and the scalar potentialφ=-E(t)y+k(t)y^(2),and find that the system has the dynamical algebra su(1,1)...Algebraic dynamics is applied to treat Landau system.We consider the case with the vector potential A=B(g)(-y,0,0)and the scalar potentialφ=-E(t)y+k(t)y^(2),and find that the system has the dynamical algebra su(1,1)㊉h⑶.With a gauge transformation the exact solutions of the system are found,of which the quantum motion in y-direction represents a harmonic oscillator with a moving origin and a varying amplitude of width,the paramertes of the gauge transformation are related to the amplitude,the velocity potential and the expectations of y and py,respectively.The energy of the system,the fluctuations of dynamical variables,the transition amplitudes between different states,and the Berry phase are calculated.展开更多
Persistent circulating currents in a mesoscopic open ring with side-branch structures are derived by transfer matrix method in the framework of quantum waveguide theory on networks.The behavior of transmission probabi...Persistent circulating currents in a mesoscopic open ring with side-branch structures are derived by transfer matrix method in the framework of quantum waveguide theory on networks.The behavior of transmission probability may show the Fano resonance in the presence of geometric scattering of side-branch structures.It is shown that persistent circulating currents in the main loop with equal length of both arms in the absence of magnetic Aux occur near the Fermi wave vectors where the Fano resonance appears.The numerical results show that a larger persistent current is associated with a stronger Fano resonance.The persistent circulating currents can be controlled by the Aux of side-branch structure.展开更多
基金The project supported in part by National Natural Science Foundation of China under Grant Nos. 10175029, 10375039, and 10647007, the Doctoral Education Fund of Ministry of Education, the Research Fund of Nuclear Theory Center of HIRFL of China, and the Science and Technology Foundation of Sichuan Province under Grant No. 02GY029-189
基金Supported in part by the National Natural Science Foundation of China under Grant Nos 107751000 and 10974137, and the Fund of Nuclear Theory Center of HIRFL of China.
文摘与限制潜力和混合相互作用，在 u 上混合介子的风味， d，和 s 夸克部门的苏(3 ) 风味基于轻锥的有效 Hamiltonian 被调查。混合向量和假向量介子的风味的集体 eigen 方程被解决。计算群众在对试验性的数据的好同意。[从作者抽象]
基金Supported by National Natural Science Foundation of China under Grant Nos.10775100 and 10974137
文摘If a coherent perturbation field is used to couple the excited level of the coupling transition in the five-levelK-type atom with another higher excited level,the two-photon electromagnetically induced transparency can be locallymodulated by altering the parameters of the additional perturbation field.With different detunings of the coherentperturbation field,the absorption peak or transparency window with sharp and high-contrast spectral feature can begenerated in the two-photon absorption spectrum.The physical interpretation of these phenomena is given in terms ofthe dressed states.
基金National Natural Science Foundation of China under Grant Nos.10205007,10226033,10375039,and 90503008the Nuclear Theory Research Program for NCET and Fund of HIRFL of China
文摘In this paper we present systematic differential representations for the dynamical group SO(4).Theserepresentations include the left and the right differential representations and the left and the right adjoint differentialrepresentations in both the group parameter space and its coset spaces.They are the generalization of the differentialrepresentations of the SO(3) rotation group in the Euler angles.These representations may find their applications in thestudy of the physical systems with SO(4) dynamical symmetry.
基金supported by National Natural Science Foundation of China under Grant Nos.10375039 and 90503008the Doctoral Fund of Ministry of Education of Chinapartly by the Center of Theoretical Nuclear Physics of HIRFL of China
文摘We find that in a supersymmetric quantum mechanics (SUSY QM) system,in addition to supersymmetric algebra,an associated SU(2) algebra can be obtained by using semiunitary (SUT) operator and projection operator, and the relevant constants of motion can be constructed.Two typical quantum systems are investigated as examples to demonstrate the above finding.The first example is the quantum system of a nonrelativistic charged particle moving in x-y plane and coupled to a magnetic field along z-axis.The second example is provided with the Dirac particle in a magnetic field.Similarly there exists an SUr(2)(?)SU_σ(2) symmetry in the context of the relativistic Pauli Hamiltonian squared.We show that there exists also an SU(2) symmetry associated with the supersymmetry of the Dirac particle.
基金National Natural Science Foundation of China under Grant Nos.90503088 and 10775100the Fund of Theoretical Nuclear Center of HIRFL of China
文摘Due to interaction with the vacuum of the radiation field,a K-type atomic system with near-degenerateexcited and ground levels,which is driven by two strong coherent fields and two weak probe fields,has additional coherenceterms—the vacuum-induced coherence (VIC) terms.In this paper,we find that,if the interference is optimized,thetwo-photon absorption properties of this atom system can be significantly modified and electromagnetically-inducedtransparency (EIT) is dependent on this interference.Furthermore,we find that in all the cases the coherence can suppressor enhance the partial two-photon transparency,while the complete transparency window is still strictly preserved,whichmeans that it cannot be affected by the VIC.Another important result is the finding of the crucial role played by therelative phase between the probe and coupling fields:the relative height of absorption peaks can be modulated by therelative phase.The physical interpretation of the phenomena has been given.
基金Supported by the National Natural Science Foundation of China under Grant No.19775020the Special Fund for Theoretical Physics,the Doctoral Education Fund of the Education Ministry,the Nuclear Research Fund of Heavy Ion Research Facility at Lanzhou of China.
文摘Algebraic dynamics is applied to treat Landau system.We consider the case with the vector potential A=B(g)(-y,0,0)and the scalar potentialφ=-E(t)y+k(t)y^(2),and find that the system has the dynamical algebra su(1,1)㊉h⑶.With a gauge transformation the exact solutions of the system are found,of which the quantum motion in y-direction represents a harmonic oscillator with a moving origin and a varying amplitude of width,the paramertes of the gauge transformation are related to the amplitude,the velocity potential and the expectations of y and py,respectively.The energy of the system,the fluctuations of dynamical variables,the transition amplitudes between different states,and the Berry phase are calculated.
基金Supported in part by the National Natural Science Foundation of China under Grant No.19475017the Doctoral Education Fund of the State Education Commission of China under Grant No.9373010.
文摘Persistent circulating currents in a mesoscopic open ring with side-branch structures are derived by transfer matrix method in the framework of quantum waveguide theory on networks.The behavior of transmission probability may show the Fano resonance in the presence of geometric scattering of side-branch structures.It is shown that persistent circulating currents in the main loop with equal length of both arms in the absence of magnetic Aux occur near the Fermi wave vectors where the Fano resonance appears.The numerical results show that a larger persistent current is associated with a stronger Fano resonance.The persistent circulating currents can be controlled by the Aux of side-branch structure.
