LiCoO_(2)is an important category of active cathode materials in lithium-ion batteries due to its high compacted electrode density,good thermal stability,and stable voltage platform.Recent works on LiCoO_(2)have focus...LiCoO_(2)is an important category of active cathode materials in lithium-ion batteries due to its high compacted electrode density,good thermal stability,and stable voltage platform.Recent works on LiCoO_(2)have focused on the realization of higher charging voltages to fully utilize its high theoretical capacity.However,an unambiguous atomic-level local probe is essential for the understanding of structure-function correlation.Here we employ highresolution solid-state nuclear magnetic resonance(NMR)spectroscopy to study the local atomic environments in LiCoO_(2)synthesized with three common sintering methods.While one-dimensional 7Li NMR shows distinct linewidth and subtle dependence on lithium over-stoichiometry,both 7Li and 59Co relaxation times are highly dependent on the sintering method.We prove that the two-step sintering method favors the elimination of unreacted Co3O4,thereby enabling the best discharge capacity in all-solid-state lithium batteries assembled with LiCoO_(2)/LGPS/LiIn,which is in accordance with its narrowest 7Li linewidth and the longest 7Li/59Co T1.展开更多
Nyquist pulses have wide applications in many areas,from electronics to optics.Mode-locked lasers are ideal platforms to generate such pulses.However,how to generate high-quality Nyquist pulses in mode-locked lasers r...Nyquist pulses have wide applications in many areas,from electronics to optics.Mode-locked lasers are ideal platforms to generate such pulses.However,how to generate high-quality Nyquist pulses in mode-locked lasers remains elusive.We address this problem by managing different physical effects in mode-locked fiber lasers through extensive numerical simulations.We find that net dispersion,linear loss,gain and filter shaping can affect the quality of Nyquist pulses significantly.We also demonstrate that Nyquist pulses experience similariton shaping due to the nonlinear attractor effect in the gain medium.Our work may contribute to the design of Nyquist pulse sources and enrich the understanding of pulse shaping dynamics in mode-locked lasers.展开更多
Besides the diverse investigations on the interactions between intense laser fields and molecular systems,extensive research has been recently dedicated to exploring the response of nanosystems excited by well-tailore...Besides the diverse investigations on the interactions between intense laser fields and molecular systems,extensive research has been recently dedicated to exploring the response of nanosystems excited by well-tailored femtosecond laser fields.Due to the fact that nanostructures hold peculiar effects when illuminated by laser pulses,the underlying mechanisms and the corresponding potential applications can make significant improvements in both fundamental research and development of novel techniques.In this review,we provide a summarization of the strong field ionization occurring on the surface of nanosystems.The molecules attached to the nanoparticle surface perform as the precursor in the ionization and excitation of the whole nanosystem,the fundamental processes of which are yet to be discovered.We discuss the influence on nanoparticle constituents,geometric shapes and sizes,as well as the specific waveforms of the excitation laser fields.The intriguing characteristics observed in surface ion emission reflect how enhanced near field affects the localized ionizations and nanoplasma expansions,thereby paving the way for further precision controls on the light-and-matter interactions in the extreme spatial temporal levels.展开更多
By numerically solving the two-dimensional semiconductor Bloch equation,we study the high-order harmonic emission of a monolayer ZnO under the driving of co-rotating two-color circularly polarized laser pulses.By chan...By numerically solving the two-dimensional semiconductor Bloch equation,we study the high-order harmonic emission of a monolayer ZnO under the driving of co-rotating two-color circularly polarized laser pulses.By changing the relative phase between the fundamental frequency field and the second one,it is found that the harmonic intensity in the platform region can be significantly modulated.In the higher order,the harmonic intensity can be increased by about one order of magnitude.Through time-frequency analysis,it is demonstrated that the emission trajectory of monolayer ZnO can be controlled by the relative phase,and the harmonic enhancement is caused by the second quantum trajectory with the higher emission probability.In addition,near-circularly polarized harmonics can be generated in the co-rotating two-color circularly polarized fields.With the change of the relative phase,the harmonics in the platform region can be altered from left-handed near-circularly polarization to right-handed one.Our results can obtain high-intensity harmonic radiation with an adjustable ellipticity,which provides an opportunity for syntheses of circularly polarized attosecond pulses.展开更多
The modulation transfer spectroscopy in an ytterbium hollow cathode lamp at 399 nm is measured.The error signal for frequency locking is optimized by measuring the dependences of its slope,linewidth and magnitude on v...The modulation transfer spectroscopy in an ytterbium hollow cathode lamp at 399 nm is measured.The error signal for frequency locking is optimized by measuring the dependences of its slope,linewidth and magnitude on various parameters.Under the optimum condition,the laser frequency at 399 nm can be stabilized.The long-term stability of laser frequency is measured by monitoring the fluorescence signal of the ytterbium atomic beam induced by the locked laser.The laser frequency is shown to be tightly locked,and the stabilized laser is successfully applied to the cooling of ytterbium atoms.展开更多
Using two tripartite Greenberger–Horne–Zeilinger(GHZ)states as the shared channels,we investigate the noise effects on the deterministic joint remote preparation of an arbitrary two-qubit state.By unitary matrix dec...Using two tripartite Greenberger–Horne–Zeilinger(GHZ)states as the shared channels,we investigate the noise effects on the deterministic joint remote preparation of an arbitrary two-qubit state.By unitary matrix decomposition procedure,we first construct the quantum logic circuit of the deterministic joint remote state preparation protocol.Then,we analytically derive the fidelity and the average fidelity for the deterministic joint remote preparation of an arbitrary twoqubit state and of four types of special two-qubit states under the influence of the Pauli noises.It is found that the fidelity depends on the noise types,the qubit-environment coupling strength,and the state to be remotely prepared.Moreover,even if the two GHZ channels are subject to the same environmental noises,the average fidelities for remotely preparing different two-qubit states display different time evolution behaviors.The remote preparation of the identical two-qubit states also shows that the average fidelities affected by different noisy environments exhibit different evolution actions.展开更多
We present the experimental study of modulation transfer spectroscopy of ytterbium atoms in a hollow cathode lamp.The dependences of its linewidth,slope and magnitude on the various experimental parameters are measure...We present the experimental study of modulation transfer spectroscopy of ytterbium atoms in a hollow cathode lamp.The dependences of its linewidth,slope and magnitude on the various experimental parameters are measured and fitted by the well-known theoretical expressions.The experimental results are in good agreement with the theoretical prediction.We have observed the Dicke narrowing effect by increasing the current of the hollow cathode lamp.It is also found that there are the optimal current and laser power to generate the better modulation transfer spectroscopy signal,which can be employed for locking the laser frequency to the atomic transition.展开更多
The localized surface plasmon resonance properties of Al and Alcore/Al2O3 shell nanosphere dimers with Al and Al core nanosphere radii of 20 nm and Al2O3 shell of 2 nm in the deep-ultraviolet region have been studied ...The localized surface plasmon resonance properties of Al and Alcore/Al2O3 shell nanosphere dimers with Al and Al core nanosphere radii of 20 nm and Al2O3 shell of 2 nm in the deep-ultraviolet region have been studied using the finite difference time domain method. The extinction spectra and the electric field distribution profiles of the two dimers for various gap distances between two individual nanospheres are compared with those of the corresponding monomers to reveal the extent of plasmon coupling. It is found that with the interparticle distance decreasing, a strong plasmon coupling between two Al or Alcore/Al2O3 shell nanospheres is observed accompanied by a significant red shift in the extinction spectra at the parallel polarization direction of the incident light related to the dimer axis, while for the case of the perpendicular polarization direction, a weak plasmon coupling arises characterized by a slight blue shift in the extinction spectra. The electric field distribution profiles show that benefiting from the dielectric Al2O3 shell, the gap distance of Alcore/Al2O3 shell nanosphere dimers can be tailored to < 1 nm scale and results in a very high electric field enhancement. The estimated surface-enhanced Raman scattering enhancement factors suggests that the Alcore/Al2O3 shell nanosphere dimers with the gap of < 1 nm gave rise to an enhancement as high as 8.1 × 107 for interparticle gap = 0.5 nm. Our studies reveal that the Alcore/Al2O3 shell nanosphere dimers may be promising substrates for surface-enhanced spectroscopy in the deep-ultraviolet region.展开更多
A near-resonant, red-detuning laser-assisted Stark deceleration scheme is proposed to slow CaF in its high-fieldseeking rovibronic ground state. The assisting Gaussian laser beam can confine CaF molecules transversely...A near-resonant, red-detuning laser-assisted Stark deceleration scheme is proposed to slow CaF in its high-fieldseeking rovibronic ground state. The assisting Gaussian laser beam can confine CaF molecules transversely owing to the optical Stark effect. Simulations suggest that the present scheme is superior to previous Stark decelerators. Under typical experimental conditions, when the assisting laser frequency is red-detuned to the molecular transition(λ～606.3 nm) by5.0 GHz and the laser power is about 5.6 W, the proposed decelerator can achieve a total number at the order of 10~4 CaF molecules with a number density at the order of 10~8 cm^(-3). The equivalent temperature of the obtained cold CaF molecules is 2.3 mK. Additionally, the desired assisting laser power can be as low as about 1.2 W if keeping the red-detuning value to be 1.0 GHz, which further suggests its experimental feasibility.展开更多
Hyperfine structures of ICl in its vibronic ground state due to the nuclear spin and electric quadruple interactions are determined by diagonalizing the effective Hamiltonian matrix. Furthermore, the Stark sub-levels ...Hyperfine structures of ICl in its vibronic ground state due to the nuclear spin and electric quadruple interactions are determined by diagonalizing the effective Hamiltonian matrix. Furthermore, the Stark sub-levels are precisely determined as well. The results are helpful for electro-static manipulation(trapping or further cooling) of cold ICl molecules. For example, an electric field of 1000 V/cm can trap ICl molecules less than 637 μK in the lowest hyperfine level.展开更多
We present an optical scheme to almost completely teleport a bipartite entangled coherent state using afour-partite cluster-type entangled coherent state as quantum channel.The scheme is based on optical elements such...We present an optical scheme to almost completely teleport a bipartite entangled coherent state using afour-partite cluster-type entangled coherent state as quantum channel.The scheme is based on optical elements suchas beam splitters,phase shifters,and photon detectors.We also obtain the average fidelity of the teleportation process.It is shown that the average fidelity is quite close to unity if the mean photon number of the coherent state is not toosmall.展开更多
As one of the biological endogenous pigments,biliverdin(BV)and its dimethyl ester(BVE)have extremely weak uorescence in solution with quantum yield less than 0.01%.However,the situation reverses with the addition of z...As one of the biological endogenous pigments,biliverdin(BV)and its dimethyl ester(BVE)have extremely weak uorescence in solution with quantum yield less than 0.01%.However,the situation reverses with the addition of zinc ions.The strength for uorescence of BVE-Zn^2+ complex is greatly enhanced and uorescence quantum yield can increase to5%.Herein,we studied ultrafast excited state dynamics of BVE-Zn^2+ complex in ethanol,npropanol,and DMSO solutions in order to reveal the mechanism of uorescence quantum yield enhancement.The results show that BVE can form a stable coordination complex with zinc with 1:1 stoichiometry in solution.BVE is structurally and energetically more stable in the complex.Using picosecond time-resolve uorescence and femtosecond transient absorption spectroscopy,we show that smaller non-radiative rate constant of BVE-Zn^2+ complex in DMSO is the key to increasing its uorescence quantum yield and the excited state decay mechanism is also revealed.These results provide valuable information about the uorescence property change after BVE binding to metal ions and may provide a guidance for the study of phytochromes or other uorescence proteins in which BV/BVE acts as chromophores.展开更多
Using a quantum channel consisting of a GHZ state exposed to noisy environment,we investigate how toremotely prepare an entangled state and a qubit state,respectively.By solving the master equation in the Lindbladform...Using a quantum channel consisting of a GHZ state exposed to noisy environment,we investigate how toremotely prepare an entangled state and a qubit state,respectively.By solving the master equation in the Lindbladform,the influence of the various types of noises on the GHZ state is first discussed.Then we use the fidelity to describehow close the remotely prepared state and the initial state are.Our results show that the fidelity is a function of thedecoherence rates and the angles of the initial state.It is found that for each of the two RSP schemes,the influence ofthe noise acting simultaneously in x,y,and z directions on the average fidelity is the strongest while the influence of thenoise acting in x or z direction on the average fidelity is relatively weaker.展开更多
We present a scheme for conclusive teleportation of an arbitrary and unknown three-particle state by per-forming three Bell-state measurements at the sender's side and a positive operator-valued measurement at the...We present a scheme for conclusive teleportation of an arbitrary and unknown three-particle state by per-forming three Bell-state measurements at the sender's side and a positive operator-valued measurement at the receiver'sside.Moreover,we obtain the successful probability of teleportation and make a brief discussion on the average fidelityfor the conclusive teleportation scheme.展开更多
We theoretically demonstrate that the(2+1)resonance-enhanced multiphoton-ionization(REMPI)photoelectron spectrum in a cesium(Cs)atom can be effectively manipulated by two time-delayed femtosecond laser pulses,involvin...We theoretically demonstrate that the(2+1)resonance-enhanced multiphoton-ionization(REMPI)photoelectron spectrum in a cesium(Cs)atom can be effectively manipulated by two time-delayed femtosecond laser pulses,involving its photoelectron spectral structure and photoelectron energy.We show that the photoelectron spectrum exhibits interference fringes and the fringe spacing is determined by the time delay of the two laser pulses,and the photoelectron energy is periodically modulated and the modulation period is determined by the two-photon transition frequency of the excited state.Finally,we utilize the power spectrum of the two time-delayed laser pulses and the two-photon transition probability of the excited state to respectively explain the modulations of the photoelectron spectrum and photoelectron energy.展开更多
Strongly-interacting Rydberg atomic ensembles have shown intense collective excitation effects due to the inclusion of single Rydberg excitation shared by multiple atoms in the ensemble.In this paper we investigate a ...Strongly-interacting Rydberg atomic ensembles have shown intense collective excitation effects due to the inclusion of single Rydberg excitation shared by multiple atoms in the ensemble.In this paper we investigate a counter-intuitive Rydberg excitation facilitation with a strongly-interacting atomic ensemble in the strong probe-field regime,which is enabled by the role of a control atom nearby.Differing from the case of a single ensemble,we show that,the control atom's excitation adds to a second two-photon transition onto the doubly-excited Rydberg state,arising an excitation facilitation for the ensemble atoms.Our numerical studies depending on the method of quantum Monte Carlo wave function,exhibit the observation constraints of this excitation facilitation effect under practical experimental conditions.The results obtained can provide a flexible control for the excitation of Rydberg atomic ensembles and participate further uses in developing mesoscopic Rydberg gates for multiqubit quantum computation.展开更多
We investigate the quantum squeezing of matter-wave solitons in atomic Bose-Einstein condensates.By calculating quantum fluctuations of the solitons via solving the Bogoliubov-de Gennes equations,we show that signific...We investigate the quantum squeezing of matter-wave solitons in atomic Bose-Einstein condensates.By calculating quantum fluctuations of the solitons via solving the Bogoliubov-de Gennes equations,we show that significant quantum squeezing can be realized for both bright and dark solitons.We also show that the squeezing efficiency of the solitons can be enhanced and manipulated by atom-atom interaction and soliton blackness.The results reported here are beneficial not only for understanding quantum property of matter-wave solitons,but also for promising applications of Bose-condensed quantum gases.展开更多
基金supported by grants from the National Natural Science Foundation of China(Nos.22172049,21874045)Shanghai Science and Technology Innovation Action Plan(No.19142202900)+1 种基金Fundamental Research Funds for Central Universities and Open Foundation of ECNU(42125102)ECNU multifunctional platform for innovation(EPR).
文摘LiCoO_(2)is an important category of active cathode materials in lithium-ion batteries due to its high compacted electrode density,good thermal stability,and stable voltage platform.Recent works on LiCoO_(2)have focused on the realization of higher charging voltages to fully utilize its high theoretical capacity.However,an unambiguous atomic-level local probe is essential for the understanding of structure-function correlation.Here we employ highresolution solid-state nuclear magnetic resonance(NMR)spectroscopy to study the local atomic environments in LiCoO_(2)synthesized with three common sintering methods.While one-dimensional 7Li NMR shows distinct linewidth and subtle dependence on lithium over-stoichiometry,both 7Li and 59Co relaxation times are highly dependent on the sintering method.We prove that the two-step sintering method favors the elimination of unreacted Co3O4,thereby enabling the best discharge capacity in all-solid-state lithium batteries assembled with LiCoO_(2)/LGPS/LiIn,which is in accordance with its narrowest 7Li linewidth and the longest 7Li/59Co T1.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11621404,11561121003,11727812,61775059,12074122,62022033,and 11704123)Shanghai Rising-Star Program,the Sustainedly Supported Foundation by the National Key Laboratory of Science and Technology on Space Microwave(Grant No.HTKT2022KL504008)+1 种基金Shanghai Natural Science Foundation(Grant No.23ZR1419000)the National Key Laboratory Foundation of China(Grant No.6142411196307).
文摘Nyquist pulses have wide applications in many areas,from electronics to optics.Mode-locked lasers are ideal platforms to generate such pulses.However,how to generate high-quality Nyquist pulses in mode-locked lasers remains elusive.We address this problem by managing different physical effects in mode-locked fiber lasers through extensive numerical simulations.We find that net dispersion,linear loss,gain and filter shaping can affect the quality of Nyquist pulses significantly.We also demonstrate that Nyquist pulses experience similariton shaping due to the nonlinear attractor effect in the gain medium.Our work may contribute to the design of Nyquist pulse sources and enrich the understanding of pulse shaping dynamics in mode-locked lasers.
基金Project supported by the National Natural Science Fundation of China (Grant Nos.92050105,92250301,and 12227807)。
文摘Besides the diverse investigations on the interactions between intense laser fields and molecular systems,extensive research has been recently dedicated to exploring the response of nanosystems excited by well-tailored femtosecond laser fields.Due to the fact that nanostructures hold peculiar effects when illuminated by laser pulses,the underlying mechanisms and the corresponding potential applications can make significant improvements in both fundamental research and development of novel techniques.In this review,we provide a summarization of the strong field ionization occurring on the surface of nanosystems.The molecules attached to the nanoparticle surface perform as the precursor in the ionization and excitation of the whole nanosystem,the fundamental processes of which are yet to be discovered.We discuss the influence on nanoparticle constituents,geometric shapes and sizes,as well as the specific waveforms of the excitation laser fields.The intriguing characteristics observed in surface ion emission reflect how enhanced near field affects the localized ionizations and nanoplasma expansions,thereby paving the way for further precision controls on the light-and-matter interactions in the extreme spatial temporal levels.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(Grant Nos.Y23A040001 and LY21F050001)the National Key Research and Development Program of China(Grant No.2019YFA0307700),the National Natural Science Foundation of China(Grant Nos.12074145,11774219,11975012,12374029,12304378,and 12204214)+2 种基金the Jilin Provincial Research Foundation for Basic Research,China(Grant No.20220101003JC)the Foundation of Education Department of Liaoning Province,China(Grant No.LJKMZ20221435)the National College Students Innovation and Entrepreneurship Training Program(Grant No.202310350062).
文摘By numerically solving the two-dimensional semiconductor Bloch equation,we study the high-order harmonic emission of a monolayer ZnO under the driving of co-rotating two-color circularly polarized laser pulses.By changing the relative phase between the fundamental frequency field and the second one,it is found that the harmonic intensity in the platform region can be significantly modulated.In the higher order,the harmonic intensity can be increased by about one order of magnitude.Through time-frequency analysis,it is demonstrated that the emission trajectory of monolayer ZnO can be controlled by the relative phase,and the harmonic enhancement is caused by the second quantum trajectory with the higher emission probability.In addition,near-circularly polarized harmonics can be generated in the co-rotating two-color circularly polarized fields.With the change of the relative phase,the harmonics in the platform region can be altered from left-handed near-circularly polarization to right-handed one.Our results can obtain high-intensity harmonic radiation with an adjustable ellipticity,which provides an opportunity for syntheses of circularly polarized attosecond pulses.
基金Project supported by the National Natural Science Foundation of China(Grant No.10774044)the National Key Basic Research and Development Program of China(Grant No.2010CB922903)+1 种基金the Science and Technology Commission of Shanghai Municipality of China(Grant No.07JC14019)Shanghai Pujiang Talent Program of China(Grant No.07PJ14038)
文摘The modulation transfer spectroscopy in an ytterbium hollow cathode lamp at 399 nm is measured.The error signal for frequency locking is optimized by measuring the dependences of its slope,linewidth and magnitude on various parameters.Under the optimum condition,the laser frequency at 399 nm can be stabilized.The long-term stability of laser frequency is measured by monitoring the fluorescence signal of the ytterbium atomic beam induced by the locked laser.The laser frequency is shown to be tightly locked,and the stabilized laser is successfully applied to the cooling of ytterbium atoms.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11174081,11034002,11104075,and 11134003)the National Basic Research Program of China (Grant Nos.2011CB921602 and 2012CB821302)the Open Fund from the SKLPS of ECNU
文摘Using two tripartite Greenberger–Horne–Zeilinger(GHZ)states as the shared channels,we investigate the noise effects on the deterministic joint remote preparation of an arbitrary two-qubit state.By unitary matrix decomposition procedure,we first construct the quantum logic circuit of the deterministic joint remote state preparation protocol.Then,we analytically derive the fidelity and the average fidelity for the deterministic joint remote preparation of an arbitrary twoqubit state and of four types of special two-qubit states under the influence of the Pauli noises.It is found that the fidelity depends on the noise types,the qubit-environment coupling strength,and the state to be remotely prepared.Moreover,even if the two GHZ channels are subject to the same environmental noises,the average fidelities for remotely preparing different two-qubit states display different time evolution behaviors.The remote preparation of the identical two-qubit states also shows that the average fidelities affected by different noisy environments exhibit different evolution actions.
基金Supported by the National Natural Science Foundation of China under Grant No 10774044the National Key Basic Research Program of China under Grant No 2010CB922903Shanghai Pujiang Talent Program under Grant No 07PJ14038.
文摘We present the experimental study of modulation transfer spectroscopy of ytterbium atoms in a hollow cathode lamp.The dependences of its linewidth,slope and magnitude on the various experimental parameters are measured and fitted by the well-known theoretical expressions.The experimental results are in good agreement with the theoretical prediction.We have observed the Dicke narrowing effect by increasing the current of the hollow cathode lamp.It is also found that there are the optimal current and laser power to generate the better modulation transfer spectroscopy signal,which can be employed for locking the laser frequency to the atomic transition.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11274116, 113740995 and 1132004, the Shanghai Science and Technology Commission under Grant Nos 11JC1403500 and 10XD1401800, the National Special Science Research Program of China under Grant Nos 2010CB923203 and 2011CB808105, and the Program of Introducing Talents of Discipline to Universities under Grant No B12024.
基金supported by the National Natural Science Foundation of China(Grant Nos.11104079 and 61378033)the National Key Scientific Instrument Project of China(Grant No.2012YQ150092)+1 种基金the Research Foundation for the Doctoral Program of Higher Education of China(Grant No.20110076120019)the State Key Laboratory of Luminescent Materials and Devices at South China University of Technology
文摘The localized surface plasmon resonance properties of Al and Alcore/Al2O3 shell nanosphere dimers with Al and Al core nanosphere radii of 20 nm and Al2O3 shell of 2 nm in the deep-ultraviolet region have been studied using the finite difference time domain method. The extinction spectra and the electric field distribution profiles of the two dimers for various gap distances between two individual nanospheres are compared with those of the corresponding monomers to reveal the extent of plasmon coupling. It is found that with the interparticle distance decreasing, a strong plasmon coupling between two Al or Alcore/Al2O3 shell nanospheres is observed accompanied by a significant red shift in the extinction spectra at the parallel polarization direction of the incident light related to the dimer axis, while for the case of the perpendicular polarization direction, a weak plasmon coupling arises characterized by a slight blue shift in the extinction spectra. The electric field distribution profiles show that benefiting from the dielectric Al2O3 shell, the gap distance of Alcore/Al2O3 shell nanosphere dimers can be tailored to < 1 nm scale and results in a very high electric field enhancement. The estimated surface-enhanced Raman scattering enhancement factors suggests that the Alcore/Al2O3 shell nanosphere dimers with the gap of < 1 nm gave rise to an enhancement as high as 8.1 × 107 for interparticle gap = 0.5 nm. Our studies reveal that the Alcore/Al2O3 shell nanosphere dimers may be promising substrates for surface-enhanced spectroscopy in the deep-ultraviolet region.
基金Project supported by the National Natural Science Foundation of China(Grant No.11604164)
文摘A near-resonant, red-detuning laser-assisted Stark deceleration scheme is proposed to slow CaF in its high-fieldseeking rovibronic ground state. The assisting Gaussian laser beam can confine CaF molecules transversely owing to the optical Stark effect. Simulations suggest that the present scheme is superior to previous Stark decelerators. Under typical experimental conditions, when the assisting laser frequency is red-detuned to the molecular transition(λ～606.3 nm) by5.0 GHz and the laser power is about 5.6 W, the proposed decelerator can achieve a total number at the order of 10~4 CaF molecules with a number density at the order of 10~8 cm^(-3). The equivalent temperature of the obtained cold CaF molecules is 2.3 mK. Additionally, the desired assisting laser power can be as low as about 1.2 W if keeping the red-detuning value to be 1.0 GHz, which further suggests its experimental feasibility.
基金supported by the National Natural Science Foundation of China(Grant No.11034002)the National Basic Research Program of China(Grant No.2011CB921602)Qing Lan Project,China
文摘Hyperfine structures of ICl in its vibronic ground state due to the nuclear spin and electric quadruple interactions are determined by diagonalizing the effective Hamiltonian matrix. Furthermore, the Stark sub-levels are precisely determined as well. The results are helpful for electro-static manipulation(trapping or further cooling) of cold ICl molecules. For example, an electric field of 1000 V/cm can trap ICl molecules less than 637 μK in the lowest hyperfine level.
基金Supported by the National Natural Science Foundation of China under Grant No.60708003the National Key Basic Research Program of China under Grant No.2006CB921604the Basic Key Program of Shanghai Municipality under Grant No.07JC14017
文摘We present an optical scheme to almost completely teleport a bipartite entangled coherent state using afour-partite cluster-type entangled coherent state as quantum channel.The scheme is based on optical elements suchas beam splitters,phase shifters,and photon detectors.We also obtain the average fidelity of the teleportation process.It is shown that the average fidelity is quite close to unity if the mean photon number of the coherent state is not toosmall.
基金The project supported by the State Key Basic Research and Development Program of China under Grant No.2006CB921604National Natural Science Foundation of China under Grant Nos.60708003,60578050,and 10434060+1 种基金the Science Foundation of Shanghai Science and Technology Committee under Grant No.07JC14017the Director Fund of State Key Laboratory of Precision Spectroscopy
基金the National Nature Science Foundation of China(No.11674101,No.21873030 and No.91850202)。
文摘As one of the biological endogenous pigments,biliverdin(BV)and its dimethyl ester(BVE)have extremely weak uorescence in solution with quantum yield less than 0.01%.However,the situation reverses with the addition of zinc ions.The strength for uorescence of BVE-Zn^2+ complex is greatly enhanced and uorescence quantum yield can increase to5%.Herein,we studied ultrafast excited state dynamics of BVE-Zn^2+ complex in ethanol,npropanol,and DMSO solutions in order to reveal the mechanism of uorescence quantum yield enhancement.The results show that BVE can form a stable coordination complex with zinc with 1:1 stoichiometry in solution.BVE is structurally and energetically more stable in the complex.Using picosecond time-resolve uorescence and femtosecond transient absorption spectroscopy,we show that smaller non-radiative rate constant of BVE-Zn^2+ complex in DMSO is the key to increasing its uorescence quantum yield and the excited state decay mechanism is also revealed.These results provide valuable information about the uorescence property change after BVE binding to metal ions and may provide a guidance for the study of phytochromes or other uorescence proteins in which BV/BVE acts as chromophores.
基金National Natural Science Foundation of China under Grant Nos.60708003,60578050,and 10434060the State Key Basic Research Program of China under Grant No.2006CB921604+1 种基金the Shanghai Science and Technology Committee under Grant No.07JC14017the Director Fund of State Key Laboratory of Precision Spectroscopy
文摘Using a quantum channel consisting of a GHZ state exposed to noisy environment,we investigate how toremotely prepare an entangled state and a qubit state,respectively.By solving the master equation in the Lindbladform,the influence of the various types of noises on the GHZ state is first discussed.Then we use the fidelity to describehow close the remotely prepared state and the initial state are.Our results show that the fidelity is a function of thedecoherence rates and the angles of the initial state.It is found that for each of the two RSP schemes,the influence ofthe noise acting simultaneously in x,y,and z directions on the average fidelity is the strongest while the influence of thenoise acting in x or z direction on the average fidelity is relatively weaker.
基金the State Key Basic Research and Development Program of China under Grant No.2006CB921604National Natural Science Foundation of China under Grant Nos.60708003,60578050,and 10434060+1 种基金the Science Foundation of Shanghai Science and Technology Committee under Grant No.07JC14017the Director Fund of State Key Laboratory of Precision Spectroscopy
文摘We present a scheme for conclusive teleportation of an arbitrary and unknown three-particle state by per-forming three Bell-state measurements at the sender's side and a positive operator-valued measurement at the receiver'sside.Moreover,we obtain the successful probability of teleportation and make a brief discussion on the average fidelityfor the conclusive teleportation scheme.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11004060,11027403 and 51132004the Shanghai Rising-Star Program(No 12QA1400900).
文摘We theoretically demonstrate that the(2+1)resonance-enhanced multiphoton-ionization(REMPI)photoelectron spectrum in a cesium(Cs)atom can be effectively manipulated by two time-delayed femtosecond laser pulses,involving its photoelectron spectral structure and photoelectron energy.We show that the photoelectron spectrum exhibits interference fringes and the fringe spacing is determined by the time delay of the two laser pulses,and the photoelectron energy is periodically modulated and the modulation period is determined by the two-photon transition frequency of the excited state.Finally,we utilize the power spectrum of the two time-delayed laser pulses and the two-photon transition probability of the excited state to respectively explain the modulations of the photoelectron spectrum and photoelectron energy.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12174106 and 11474094)the Science and Technology Commission of Shanghai Municipality(Grant No.18ZR1412800)。
文摘Strongly-interacting Rydberg atomic ensembles have shown intense collective excitation effects due to the inclusion of single Rydberg excitation shared by multiple atoms in the ensemble.In this paper we investigate a counter-intuitive Rydberg excitation facilitation with a strongly-interacting atomic ensemble in the strong probe-field regime,which is enabled by the role of a control atom nearby.Differing from the case of a single ensemble,we show that,the control atom's excitation adds to a second two-photon transition onto the doubly-excited Rydberg state,arising an excitation facilitation for the ensemble atoms.Our numerical studies depending on the method of quantum Monte Carlo wave function,exhibit the observation constraints of this excitation facilitation effect under practical experimental conditions.The results obtained can provide a flexible control for the excitation of Rydberg atomic ensembles and participate further uses in developing mesoscopic Rydberg gates for multiqubit quantum computation.
基金supported by the National Natural Science Foundation of China(Grant No.11975098)。
文摘We investigate the quantum squeezing of matter-wave solitons in atomic Bose-Einstein condensates.By calculating quantum fluctuations of the solitons via solving the Bogoliubov-de Gennes equations,we show that significant quantum squeezing can be realized for both bright and dark solitons.We also show that the squeezing efficiency of the solitons can be enhanced and manipulated by atom-atom interaction and soliton blackness.The results reported here are beneficial not only for understanding quantum property of matter-wave solitons,but also for promising applications of Bose-condensed quantum gases.
