We demonstrate that Fokker Planck equations with logarithmic factors in diffusion and drift terms can be straightforwardly derived from the class of "constant elasticity of variance" stochastic processes without app...We demonstrate that Fokker Planck equations with logarithmic factors in diffusion and drift terms can be straightforwardly derived from the class of "constant elasticity of variance" stochastic processes without appealing to any symmetry argument, Analytical closed-form solutions are available for some special cases of this class of Fokker-Planck equations. The dynamics of the underlying stochastic variables are examined. These Fokker-Planck equations have found a rather wide range of applications in various contexts. In particular, in the field of econophysics we have demonstrated their immediate relevance to modelling the exchange rate dynamics in a target zone, e.g. the linked exchange rate system of the Hong Kong dollar. Furthermore, the knowledge of exact solutions in some special cases can be useful as a benchmark to test approximate numerical or analytical procedures.展开更多
We study theoretically the nonadiabatic geometric phase of a doubly driven two-level system with an additional relative phase between the two driving modes introduced in. It is shown that the time evolution of the sys...We study theoretically the nonadiabatic geometric phase of a doubly driven two-level system with an additional relative phase between the two driving modes introduced in. It is shown that the time evolution of the system strongly depends on this relative phase. The condition for the system returning to its initial state after a single period is given by the means of the Landau–Zener–Stückelberg–Majorana destructive interference. The nonadiabatic geometric phase accompanying a cyclic evolution is shown to be related to the Stokes phase as well as this relative phase. By controlling the relative phase, the geometric phase can characterize two distinct phases in the adiabatic limit.展开更多
The radio-frequency modulated electromagnetically induced transparency(EIT) in a ladder three-level system with Rydberg state is studied. Under the influence of a fast radio-frequency field, the EIT peak splits into a...The radio-frequency modulated electromagnetically induced transparency(EIT) in a ladder three-level system with Rydberg state is studied. Under the influence of a fast radio-frequency field, the EIT peak splits into a series of sidebands.When attaching a power-frequency electric field directly to the fast radio-frequency field, the odd-order sidebands of the Rydberg-EIT oscillate sensitively with the power-frequency field. The oscillation frequency is equal to twice the power frequency;the oscillation amplitude is monotonically increasing with the amplitude of the power-frequency field when the change of Stark-shift is smaller than the radio frequency. Our work paves the way for measurement of power-frequency electric field based on Rydberg atoms.展开更多
We theoretically investigate the control of surface plasmon polariton(SPP) generated at the interface of dielectric and graphene medium under Kerr nonlinearity. The controlled Kerr nonlinear signal of probe light be...We theoretically investigate the control of surface plasmon polariton(SPP) generated at the interface of dielectric and graphene medium under Kerr nonlinearity. The controlled Kerr nonlinear signal of probe light beam in a dielectric medium is used to generate SPPs at the interface of dielectric and graphene medium. The positive, negative absorption, and dispersion properties of SPPs are modified and controlled by the control and Kerr fields. A large amplification(negative absorption) is noted for SPPs under the Kerr nonlinearity. The normal/anomalous slope of dispersion and propagation length of SPPs is modified and controlled with Kerr nonlinearity. This leads to significant variation in slow and fast SPP propagation. The controlled slow and fast SPP propagation may predict significant applications in nano-photonics, optical tweezers, photovoltaic devices, plasmonster, and sensing technology.展开更多
The vectorial structure of an optical field with hybrid states of polarization (SOP) in the near-field is studied by using the angular spectrum method of an electromagnetic beam. Physical images of the longitudinal ...The vectorial structure of an optical field with hybrid states of polarization (SOP) in the near-field is studied by using the angular spectrum method of an electromagnetic beam. Physical images of the longitudinal components of evanescent waves are illustrated and compared with those of the transverse components from the vectorial structure. Our results indicate that the relative weight integrated over the transverse plane of the evanescent wave depends strongly on the number of the polarization topological charges. The shapes of the intensity profiles of the longitudinal components are different from those of the transverse components, and it can be manipulated by changing the initial SoP of the field cross-section. The longitudinal component of evanescent wave dominates the near-field region. In addition, it also leads to three-dimensional shape variations of the optical field and the optical spin angular momentum flux density distributions.展开更多
The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and ele...The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and electro-magnetic transition rates are derived.展开更多
The important features of the rescattering trajectories in strong field ionization process such as the cutoff of the return energy at 3.17Up and that of the final energy at 10Up are obtained, based on the adiabatic ap...The important features of the rescattering trajectories in strong field ionization process such as the cutoff of the return energy at 3.17Up and that of the final energy at 10Up are obtained, based on the adiabatic approximation in which the initial momentum of the electron is assumed to be zero. We theoretically study the nonadiabatic effect by assuming a nonzero initial momentum on the rescattering trajectories based on the semiclassical simpleman model. We show that the nonzero initial momentum will modify both the maximal return energy at collision and the final energy after backward scattering, but in different ways for odd and even number of return trajectories. The energies are increased for even number of returns but are decreased for odd number of returns when the nonzero (positive or negative) initial momentum is applied.展开更多
Nonsequential double ionization (NSDI) processes of nonaligned diatomic molecules N2 and O2 are studied using the S-matrix theory. Our results show that the NSDI process significantly depends on the molecular symmet...Nonsequential double ionization (NSDI) processes of nonaligned diatomic molecules N2 and O2 are studied using the S-matrix theory. Our results show that the NSDI process significantly depends on the molecular symmetry and structure. The ratio of NSDI rate to single ionization rate as a function of the field intensity is obtained. It is found that N2 behaves closely with its companion atom Ar in the ratios over the entire intensity range, while O2 exhibits an obvious suppression effect, which is qualitatively consistent with the experiment.展开更多
We have studied the ground state configurations of a rotating Bose-Einstein condensation in a toroidal trap as the radius of the central Gaussian potential expands adiabatically.Firstly,we observe that the vortices ar...We have studied the ground state configurations of a rotating Bose-Einstein condensation in a toroidal trap as the radius of the central Gaussian potential expands adiabatically.Firstly,we observe that the vortices are devoured successively into the central hole of the condensate to form a giant vortex as the radius of the trap expands.When all the pre-existing vortices are absorbed,the angular momentum of the system still increase as the radius of the gaussian potential enlarges.When increasing the interaction strength,we find that more singly quantized vortices are squeezed into the condensate,but the giant vortex does not change.展开更多
We propose a four-terminal device consisting of two parallel quantum dots with Rashba spin-orbit interaction (RSOI), coupled to two side superconductor leads and two common ferromagnetic leads, respectively. The two...We propose a four-terminal device consisting of two parallel quantum dots with Rashba spin-orbit interaction (RSOI), coupled to two side superconductor leads and two common ferromagnetic leads, respectively. The two ferromagnetic leads and two quantum dots form a ring threaded by Aharonov-Bohm (AB) flux. This device possesses normal quasiparticle transmission between the two ferromagnetic leads, and normal and crossed Andreev reflections providing conductive holes. For the appropriate spin polarization of the ferromagnetic leads, RSOI and AB flux, the pure spin-up (or spin-down) current without net charge current in the right lead, which is due to the equal numbers of electrons and holes with the same spin-polarization moving along the same direction, can be obtained by adjusting the gate voltage, which may be used in practice as a pure spin-current injector.展开更多
Our primary purpose of this work is to explicitly construct the general multipartite Einstein Podolsky-Rosen (EPR) entangled state in muIti-mode Fock space for a system with different masses of particles,which makes u...Our primary purpose of this work is to explicitly construct the general multipartite Einstein Podolsky-Rosen (EPR) entangled state in muIti-mode Fock space for a system with different masses of particles,which makes up anew quantum mechanical representation owing to completeness relation and orthogonal property.Its entanglement canbe seen more clearly by analyzing its standard Schmidt decomposition.In addition,some applications of the multipartiteentanglement are proposed including deriving the generalized Wigner operator and squeezing operator.展开更多
The first-principles methods have been employed to calculate the structural, electronic, and mechanical properties of the α, β, and γ phases of uranium under pressure up to 100 GPa. The electronic structure has bee...The first-principles methods have been employed to calculate the structural, electronic, and mechanical properties of the α, β, and γ phases of uranium under pressure up to 100 GPa. The electronic structure has been viewed in forms of density of states and band structure. The mechanical stability of metal U in the α, β, and γ phases have been examined.The independent elastic constants, polycrystalline elastic moduli, as well as Poisson's ratio have been obtained. Upon compression, the elastic constants, elastic moduli, elastic wave velocities, and Debye temperature of α phase are enhanced pronouncedly. The value of B/G illustrates that α and γ phases are brittle in ground state.展开更多
We introduce the so-called coherent-entangled state (CES) in the four-mode Fock space,which makesup a new quantum mechanical representation owing to completeness relation and orthogonal property.Its standardSchmidt de...We introduce the so-called coherent-entangled state (CES) in the four-mode Fock space,which makesup a new quantum mechanical representation owing to completeness relation and orthogonal property.Its standardSchmidt decomposition and experimental generation using beam-splitter (BS) are proposed.In addition,its applicationsin quantum optics are presented.Finally,we extend it to multi-mode case and discuss some applications,too.展开更多
文摘We demonstrate that Fokker Planck equations with logarithmic factors in diffusion and drift terms can be straightforwardly derived from the class of "constant elasticity of variance" stochastic processes without appealing to any symmetry argument, Analytical closed-form solutions are available for some special cases of this class of Fokker-Planck equations. The dynamics of the underlying stochastic variables are examined. These Fokker-Planck equations have found a rather wide range of applications in various contexts. In particular, in the field of econophysics we have demonstrated their immediate relevance to modelling the exchange rate dynamics in a target zone, e.g. the linked exchange rate system of the Hong Kong dollar. Furthermore, the knowledge of exact solutions in some special cases can be useful as a benchmark to test approximate numerical or analytical procedures.
基金the Special Foundation for theoretical physics Research Program of China (Grant No. 11647165)the China Postdoctoral Science Foundation Funded Project (Project No. 2020M673118)+3 种基金the funding from the National Natural Science Foundation of China (Grant No. 11874247)the National Key Research and Development Program of China (Grant No. 2017YFA0304500)the Program of State Key Laboratory of Quantum Optics and Quantum Optics Devices, China (Grant No. KF201703)the support from Guangdong Provincial Key Laboratory (Grant No. 2019B121203002)。
文摘We study theoretically the nonadiabatic geometric phase of a doubly driven two-level system with an additional relative phase between the two driving modes introduced in. It is shown that the time evolution of the system strongly depends on this relative phase. The condition for the system returning to its initial state after a single period is given by the means of the Landau–Zener–Stückelberg–Majorana destructive interference. The nonadiabatic geometric phase accompanying a cyclic evolution is shown to be related to the Stokes phase as well as this relative phase. By controlling the relative phase, the geometric phase can characterize two distinct phases in the adiabatic limit.
基金supported by the National Natural Science Foundation of China (Grant No. 12274045)the Special Foundation for Theoretical Physics Research Program of China (Grant No. 11647165)the China Postdoctoral Science Foundation Funded Project (Grant No. 2020M673118)。
文摘The radio-frequency modulated electromagnetically induced transparency(EIT) in a ladder three-level system with Rydberg state is studied. Under the influence of a fast radio-frequency field, the EIT peak splits into a series of sidebands.When attaching a power-frequency electric field directly to the fast radio-frequency field, the odd-order sidebands of the Rydberg-EIT oscillate sensitively with the power-frequency field. The oscillation frequency is equal to twice the power frequency;the oscillation amplitude is monotonically increasing with the amplitude of the power-frequency field when the change of Stark-shift is smaller than the radio frequency. Our work paves the way for measurement of power-frequency electric field based on Rydberg atoms.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10475027 and 10635040, the PPS under Grant No 05PJ14036, by SPS under Grant No 05SG27 and the NCET-05-0424.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10775052 and 10635040, the New Century Excellent Talent Project of the Ministry of Education of China under Grant No 05-0424, and the National Basic Research Program of China under Grant No 2007CB814800.
文摘We theoretically investigate the control of surface plasmon polariton(SPP) generated at the interface of dielectric and graphene medium under Kerr nonlinearity. The controlled Kerr nonlinear signal of probe light beam in a dielectric medium is used to generate SPPs at the interface of dielectric and graphene medium. The positive, negative absorption, and dispersion properties of SPPs are modified and controlled by the control and Kerr fields. A large amplification(negative absorption) is noted for SPPs under the Kerr nonlinearity. The normal/anomalous slope of dispersion and propagation length of SPPs is modified and controlled with Kerr nonlinearity. This leads to significant variation in slow and fast SPP propagation. The controlled slow and fast SPP propagation may predict significant applications in nano-photonics, optical tweezers, photovoltaic devices, plasmonster, and sensing technology.
基金supported by the Zhejiang Provincial Natural Science Foundation,China(Grant Nos.LZ17A040001 and LY16A040014)the National Natural Science Foundation of China(Grant Nos.11574271 and 11574272)+1 种基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministrythe Science Research Foundation of Zhejiang Sci-Tech University(ZSTU),China(Grant No.14062078-Y)
文摘The vectorial structure of an optical field with hybrid states of polarization (SOP) in the near-field is studied by using the angular spectrum method of an electromagnetic beam. Physical images of the longitudinal components of evanescent waves are illustrated and compared with those of the transverse components from the vectorial structure. Our results indicate that the relative weight integrated over the transverse plane of the evanescent wave depends strongly on the number of the polarization topological charges. The shapes of the intensity profiles of the longitudinal components are different from those of the transverse components, and it can be manipulated by changing the initial SoP of the field cross-section. The longitudinal component of evanescent wave dominates the near-field region. In addition, it also leads to three-dimensional shape variations of the optical field and the optical spin angular momentum flux density distributions.
文摘The interacting boson model for anomalous rotational bands is proposed. In the rotational SU(3) limit,an asymptotic limit is discussed. Within the framework of the model several analytic relations for energies and electro-magnetic transition rates are derived.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11425414 and 11504215the Scientific Research Training Program of Shanxi University
文摘The important features of the rescattering trajectories in strong field ionization process such as the cutoff of the return energy at 3.17Up and that of the final energy at 10Up are obtained, based on the adiabatic approximation in which the initial momentum of the electron is assumed to be zero. We theoretically study the nonadiabatic effect by assuming a nonzero initial momentum on the rescattering trajectories based on the semiclassical simpleman model. We show that the nonzero initial momentum will modify both the maximal return energy at collision and the final energy after backward scattering, but in different ways for odd and even number of return trajectories. The energies are increased for even number of returns but are decreased for odd number of returns when the nonzero (positive or negative) initial momentum is applied.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11074026, 11074155, and 11104225)the Program for New Century Excellent Talents in University of the Ministry of Education of China (Grant No. NCET-08-0883)the National Basic Research Program of China (Grant No. 2011CB808100)
文摘Nonsequential double ionization (NSDI) processes of nonaligned diatomic molecules N2 and O2 are studied using the S-matrix theory. Our results show that the NSDI process significantly depends on the molecular symmetry and structure. The ratio of NSDI rate to single ionization rate as a function of the field intensity is obtained. It is found that N2 behaves closely with its companion atom Ar in the ratios over the entire intensity range, while O2 exhibits an obvious suppression effect, which is qualitatively consistent with the experiment.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10475027 and 10635040, the Pujiang Project of Shanghai under Grant No 05PJ14036, the Shuguang Project of Shanghai under Grant No 05SG27, and the New Century Excellent Talent Project of the Ministry of Education of China under Grant No 05-0424.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10475027 and 10635040, the PPS under Grant No 05PJ14036, by SPS under Grant No 05SG27, and NCET-05-0424.
基金The project supported in part by National Natural Science Foundation of China under Grant No. 10174086. Luo greatly appreciates Prof. J.Z. Zhang for valuable discussions.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10904096 and 10604024the Natural Science Foundation of Beijing under Grant No.1092009
文摘We have studied the ground state configurations of a rotating Bose-Einstein condensation in a toroidal trap as the radius of the central Gaussian potential expands adiabatically.Firstly,we observe that the vortices are devoured successively into the central hole of the condensate to form a giant vortex as the radius of the trap expands.When all the pre-existing vortices are absorbed,the angular momentum of the system still increase as the radius of the gaussian potential enlarges.When increasing the interaction strength,we find that more singly quantized vortices are squeezed into the condensate,but the giant vortex does not change.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10475027 and 10635040, the Shuguang Project of Shanghai under Grant No 05SG27, the New Century Excellent Talent Project of the Ministry of Education of China under Grant No 05-0424, and the Natural Science Foundation of Jiangshu under Grant No 06KJB140110.
基金Supported by the National Natural Science Foundation of China under Grant No 10475027, by SRF for R0CS, SEM under Grant No 44020460, and the Pujiang Project of Shanghai under Grant No 05PJ14036.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10775091,10774094,10974124,and 11047172)the Excellent Youth and Midlife Scientist Scientific Research Encouragement Foundation of Shandong Province,China(Grant No. BS2010DS006)the Doctor Research Startup Foundation of Linyi University,China (Grant No. BS201023)
文摘We propose a four-terminal device consisting of two parallel quantum dots with Rashba spin-orbit interaction (RSOI), coupled to two side superconductor leads and two common ferromagnetic leads, respectively. The two ferromagnetic leads and two quantum dots form a ring threaded by Aharonov-Bohm (AB) flux. This device possesses normal quasiparticle transmission between the two ferromagnetic leads, and normal and crossed Andreev reflections providing conductive holes. For the appropriate spin polarization of the ferromagnetic leads, RSOI and AB flux, the pure spin-up (or spin-down) current without net charge current in the right lead, which is due to the equal numbers of electrons and holes with the same spin-polarization moving along the same direction, can be obtained by adjusting the gate voltage, which may be used in practice as a pure spin-current injector.
基金National Natural Science Foundation of China under Grant No.10675108the Natural Science Foundation of the Education Department of Anhui Province under Grant No.KJ2007B377ZCthe Young University Teachers' Fund of Anhui Province under Grant No.2007jql155
文摘Our primary purpose of this work is to explicitly construct the general multipartite Einstein Podolsky-Rosen (EPR) entangled state in muIti-mode Fock space for a system with different masses of particles,which makes up anew quantum mechanical representation owing to completeness relation and orthogonal property.Its entanglement canbe seen more clearly by analyzing its standard Schmidt decomposition.In addition,some applications of the multipartiteentanglement are proposed including deriving the generalized Wigner operator and squeezing operator.
基金supported by the National Natural Science Foundation of China(Grant No.11374197)
文摘The first-principles methods have been employed to calculate the structural, electronic, and mechanical properties of the α, β, and γ phases of uranium under pressure up to 100 GPa. The electronic structure has been viewed in forms of density of states and band structure. The mechanical stability of metal U in the α, β, and γ phases have been examined.The independent elastic constants, polycrystalline elastic moduli, as well as Poisson's ratio have been obtained. Upon compression, the elastic constants, elastic moduli, elastic wave velocities, and Debye temperature of α phase are enhanced pronouncedly. The value of B/G illustrates that α and γ phases are brittle in ground state.
基金supported by National Natural Science Foundation of China under Grant No.10675108the Natural Scientific Research Fund of the Education Department of Anhui Province under Grant No.KJ2007B377ZCthe Young University Teachers' Fund of Anhui Province under Grant No.2007jql155
文摘We introduce the so-called coherent-entangled state (CES) in the four-mode Fock space,which makesup a new quantum mechanical representation owing to completeness relation and orthogonal property.Its standardSchmidt decomposition and experimental generation using beam-splitter (BS) are proposed.In addition,its applicationsin quantum optics are presented.Finally,we extend it to multi-mode case and discuss some applications,too.