We propose a scheme to implement a two-qubit conditional quantum phase gate for the intracavity field via a single three-level ∧-type atom driven by two modes in a high-Q cavity. The quantum inforraation is encoded o...We propose a scheme to implement a two-qubit conditional quantum phase gate for the intracavity field via a single three-level ∧-type atom driven by two modes in a high-Q cavity. The quantum inforraation is encoded on the Fock states of the bimodal cavity. The gate＇s averaged fidelity is expected to reach 99.8%.展开更多
In this paper, we study the control problem of adiabatic decoherence in a three-level atom. We will find the decoupling bang-bang group for various configurations, including the V configuration and the cascade type of...In this paper, we study the control problem of adiabatic decoherence in a three-level atom. We will find the decoupling bang-bang group for various configurations, including the V configuration and the cascade type of three-levelatom subjected to adiabatic decoherence. We also give the programs to design a sequence of periodic twinborn pulses to suppress the decoherence.展开更多
The general expressions of the average dissipative and dipole forces acting on a A-configuration three-level atom in an arbitrary light field are derived by means of the optical Bloch equations based on the atomic den...The general expressions of the average dissipative and dipole forces acting on a A-configuration three-level atom in an arbitrary light field are derived by means of the optical Bloch equations based on the atomic density matrix elements, and the general properties of the average dissipative and dipole forces on a three-level atom in the linearly-polarized high-order Bessel beams （HBBs） are analysed. We find a resonant property （with two resonant peaks） of the dissipative force and a non-resonant property （with two pairs of non-resonant peaks） of the dipole force on the three-level atom, which are completely different from those on the two-level atom. Meanwhile we find a saturation effect of the average dissipative force in the HBB, which comes from the saturation of the upper-level population. Our study shows that the general expressions of the average dissipative and dipole forces on the three-level atom will be simplified to those of the two-level atom under the approximation of large detuning. Finally, we study the axial and azimuthal Doppler cooling of atoms in ID optical molasses composed of two counter-propagating HBBs and discuss the azimuthal influence of the HBB on the Doppler cooling limit. We also find that the Doppler limit of atoms in the molasses HBB is slightly below the conventional Doppler limit of hГ/（2kB） due to the orbital angular momentum lh of the HBB.展开更多
The entropy squeezing of a V-type three-level atom interacting with a single-mode field and passing through the amplitude damping channel is investigated in detail. Our results show that when coupled to the single-mod...The entropy squeezing of a V-type three-level atom interacting with a single-mode field and passing through the amplitude damping channel is investigated in detail. Our results show that when coupled to the single-mode field, the atom in appropriate initial states can not only generate obvious entropy squeezing but also keep in the optimal squeezing state,while passing through the amplitude damping channel, the atom can generate entropy squeezing under the control of the weak measurement. Besides, it is proved again that as a measurement method for atomic squeezing, the entropy squeezing is precise and effective. Therefore our work is instructive for experiments in preparing three-level system information resource with ultra-low quantum noise.展开更多
In a system with a moving V-type three-level atom interacting with the SU（1,1）-related coherent fields, we investigate the entanglement between the moving three-level atom and the SU（1,1）-related coherent fields b...In a system with a moving V-type three-level atom interacting with the SU（1,1）-related coherent fields, we investigate the entanglement between the moving three-level atom and the SU（1,1）-related coherent fields by using the quantum-reduced entropy, and that between the SU（1,1）-related coherent fields by using the quantum relative entropy of entanglement. It is shown that the two kinds of entanglement are dependent on the atomic motion and exhibit the periodic evolution with a period of 2π/p. The maximal atom-field qutrit entanglement state can be prepared, and the entanglement preservation of the SU（1,1）-related coherent fields can be realized in the interacting process via the appropriate selection of system parameters and interaction time.展开更多
A very simpJe theoretical scheme is proposed to implement two-and three-qubit controlled-phase gates firstly only using a single resonant interaction between ladder-type three-level atoms and the single-mode cavity. I...A very simpJe theoretical scheme is proposed to implement two-and three-qubit controlled-phase gates firstly only using a single resonant interaction between ladder-type three-level atoms and the single-mode cavity. In the presented protocol, the quantum information is encoded on the stable ground states of the atoms （as the controlling qubits） and the zero- and one-photon Fock states of cavity-field （as the target qubit）. Under the influence of the atomic spontaneous emission, the decay of the cavity-mode, and deviation of the coupling strength, the three-qubit controlled- phase gate may have a comparatively high fidelity. The experimental feasibility of controlled-phase gate and the ease that is extended to realize N-qubit controlled-phase gate are also discussed.展开更多
We have studied theoretically and numerically the enhanced cooling of a V-type three-level atom in a high-finesse optical cavity and shown that the cooling rate can be increased by one order of magnitude over that of ...We have studied theoretically and numerically the enhanced cooling of a V-type three-level atom in a high-finesse optical cavity and shown that the cooling rate can be increased by one order of magnitude over that of a two-level atom, and the momentum amplitude tends to a stationary state much smaller than that of a two-level atom. We have further shown that the cooling rate can be significantly improved by using feedback and a time-dependent pump.展开更多
Polarization, an intrinsic ingredient of photon, plays a critical role in its interaction with matter. A general polarization state can be an appropriate superposition of two basic polarization states, say, the vertic...Polarization, an intrinsic ingredient of photon, plays a critical role in its interaction with matter. A general polarization state can be an appropriate superposition of two basic polarization states, say, the vertical and horizontal linear polarized state. Here we study spontaneous emission of a V-type three-level atom（with two upper states close in energy level）strongly coupled with a single-mode damped optical cavity. By defining a general polarization state of atom as a specific superposition of the two upper quantum states, we can prepare atoms with linear polarization at arbitrary direction, left and right circular polarization, and left and right elliptical polarization, similar to photons. We find that the spontaneous emission of light from these ＂polarized＂ three-level atoms shows very different profiles of side and axis spectra. This means that the polarization state of three-level atoms can become an active ingredient to manipulate its interaction with light and control the quantum interference effect. Exploitation of the coherent superposition and interference of quantum states in＂polarized＂ atoms would allow one to deeply explore new frontiers of light–matter interaction.展开更多
This paper proposes a scheme for the generation of entangled coherent states for two cavity modes. In the scheme a V-type three-level atom is sent through a two-mode cavity filled with a coherent field. After the atom...This paper proposes a scheme for the generation of entangled coherent states for two cavity modes. In the scheme a V-type three-level atom is sent through a two-mode cavity filled with a coherent field. After the atom cavity interaction and detection of the atomic state the cavity modes may evolve to a superposition of two-mode coherent states. As the scheme is based on resonant atom-cavity interaction, the required interaction time is short, which is important in view of the decoherence. Moreover, additional classical pulses are unnecessary before and after the atom-cavlty interaction.展开更多
A theoretical study is carried out for the modification and implication of the effect on the type three level atom in a high-finesse optical cavity driven by light field including spontaneous emission and the cavity d...A theoretical study is carried out for the modification and implication of the effect on the type three level atom in a high-finesse optical cavity driven by light field including spontaneous emission and the cavity decay. Analytic expressions for the dipole force, the friction force, the optical potentials and the friction coefficient are obtained. Then the numerical and graphical methods are used to investigate the friction coefficient with the controlling parameters. It is shown that the friction coefficient is strongly dependent on the controlling parameters. The cooling rate can increase by one order of magnitude more than that of a two-level atomic system. The reason can be given using the dressed states and the Sisyphus cooling mechanism, which would stimulate further experimental investigations.展开更多
We theoretically investigate the emission spectrum for a A-type three-level atom trapped in the node of a standing wave. We show that the atomic center-of-mass motion not only directly affects the peak number, peak po...We theoretically investigate the emission spectrum for a A-type three-level atom trapped in the node of a standing wave. We show that the atomic center-of-mass motion not only directly affects the peak number, peak position, and peak height in the atomic emission spectrum, but also influences the effects of the cavity field and the atomic initial state on atomic emission spectrum.展开更多
We study the features of electromagnetically induced transparency（EIT） in a single Λ-type three-level atom placed in a high-finesse cavity under the action of a coupling laser and a probe laser.Our calculations sho...We study the features of electromagnetically induced transparency（EIT） in a single Λ-type three-level atom placed in a high-finesse cavity under the action of a coupling laser and a probe laser.Our calculations show that three transparency windows appear when the pump strength is large enough.This can be explained by the residual pump in the cavity mostly resulting in energy splitting.The level ｜3 is split into four slightly different energy levels,and interference takes place between the excitation pathways.Furthermore,it is also shown that the frequencies of the EIT windows can be tuned by changing the coupling field detuning 2,and that the reflection profile is very sensitive to the cavity field detuning △c.展开更多
A scheme is proposed for generating maximally entangled states for two or more three-level atoms. In the scheme the atoms are sent through a two-mode cavity one by one and interact with the two-cavity modes sequential...A scheme is proposed for generating maximally entangled states for two or more three-level atoms. In the scheme the atoms are sent through a two-mode cavity one by one and interact with the two-cavity modes sequentially. The required experimental techniques are within the scope of what can be obtained in the microwave cavity QED setup.展开更多
A scheme is presented for generating entangled states for two three-level atoms in a cavity. In the scheme two atoms simultaneously interact with a cavity mode with a small detuning. Thus, the operation time is very ...A scheme is presented for generating entangled states for two three-level atoms in a cavity. In the scheme two atoms simultaneously interact with a cavity mode with a small detuning. Thus, the operation time is very short, which is important in view of decoherence.展开更多
The cavity field spectrum of a cascade three-level atom interacting with single-mode field with Kerr-like medium in the cavity is investigated. The numerical results for the initial field in pure number state, coheren...The cavity field spectrum of a cascade three-level atom interacting with single-mode field with Kerr-like medium in the cavity is investigated. The numerical results for the initial field in pure number state, coherent state and squeezed vacuum state are calculated, respectively. It is found that the Kerr-like medium affects the spectral structure even though the initial field is in vacuum when the atom is in upper level. In the case of strong input field, the number state spectrum shows two peaks with different heights; and the superposition state spectrum shows a multipeak structure with an equal distance of two neighboring peaks. The spectral ＂central frequency＂ shifts away from the resonant frequency with the increasing of average photon number.展开更多
The entropy squeezing properties of different types of moving three-level atoms coupled with a single-mode coherent field are studied. The influences of the moving velocity and initial states of the three-level atom o...The entropy squeezing properties of different types of moving three-level atoms coupled with a single-mode coherent field are studied. The influences of the moving velocity and initial states of the three-level atom on the entropy squeezing are discussed. The results show that, the entropy squeezing properties of the three-level atom depend on its initial state, moving velocity, and the type. A stationary three-level atom can not obtain a steady entropy squeezing whatever initial conditions are chosen, while a moving three-level atom can achieve a steady and optimal entropy squeezing through choosing higher velocity and appropriate initial state. Our result provides a simple method for preparing squeezing resources with ultra-low quantum noise of the three-level atomic system without additional any complex techniques.展开更多
We study the dynamics of the entropic uncertainty for three types of three-level atomic systems coupled to an environment modeled by random matrices. The results show that the entropic uncertainty in the Ξ-type atomi...We study the dynamics of the entropic uncertainty for three types of three-level atomic systems coupled to an environment modeled by random matrices. The results show that the entropic uncertainty in the Ξ-type atomic system is lower than that in the V-type atomic system which is exactly the same as that in the Λ-type atomic system. In addition, the effect of relative coupling strength on entropic uncertainty is opposite in Markov region and non-Markov region, and the influence of a common environment and independent environments in Markov region and non-Markov region is also opposite. One can reduce the entropic uncertainty by decreasing relative coupling strength or placing the system in two separate environments in the Markov case. In the non-Markov case, the entropic uncertainty can be reduced by increasing the relative coupling strength or by placing the system in a common environment.展开更多
The Hamiltonian of coupled three-level atoms interacting with light field in the cavity filled with Kerr-like medium is derived. A simplified analytic solution to the Schrodinger equation of the system is obtained. Th...The Hamiltonian of coupled three-level atoms interacting with light field in the cavity filled with Kerr-like medium is derived. A simplified analytic solution to the Schrodinger equation of the system is obtained. The case of A type atom with degenerate lower levels is discussed in detail. It is shown that the coupling strength between atoms and Kerr coefficient affect the system＇s dynamic behaviors, especially the modulation period and oscillation frequency of the squeezing parameters of the field and the collective dipole moment. Dynamic behaviors of the system are sensitive to the initial state of atoms.展开更多
We use the relative phase difference of two bichromatic fields of equal frequency differences for the coherent control of spontaneous emission of a three-level atom in the A configuration, diffects such as selective a...We use the relative phase difference of two bichromatic fields of equal frequency differences for the coherent control of spontaneous emission of a three-level atom in the A configuration, diffects such as selective and total cancellation of fluorescence decay are obtained simply by varying the phase difference. The phese dependence of fluorescence spectra is attributed to the fact that the four different field components induce the transitions in a closed loop configuratiou.展开更多
In this paper,we present decoupling bang-bang operations for the suppression of general decoherence,bothamplitude and phase damping,in a three-level system in A-configuration.We give a program to design a sequence ofp...In this paper,we present decoupling bang-bang operations for the suppression of general decoherence,bothamplitude and phase damping,in a three-level system in A-configuration.We give a program to design a sequence ofperiodic twinborn pulses to suppress the decoherence in such the system.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 10374025）.
文摘We propose a scheme to implement a two-qubit conditional quantum phase gate for the intracavity field via a single three-level ∧-type atom driven by two modes in a high-Q cavity. The quantum inforraation is encoded on the Fock states of the bimodal cavity. The gate＇s averaged fidelity is expected to reach 99.8%.
文摘In this paper, we study the control problem of adiabatic decoherence in a three-level atom. We will find the decoupling bang-bang group for various configurations, including the V configuration and the cascade type of three-levelatom subjected to adiabatic decoherence. We also give the programs to design a sequence of periodic twinborn pulses to suppress the decoherence.
基金supported by the National Natural Science Foundation of China (Grant Nos 10434060 and 10674047)the Natural Science Foundation of the Jiangsu Higher Institutions of China (Grant No 06KJB510020)the Natural Science Foundation of Jiangsu University of China (Grant No 07JDG027)
文摘The general expressions of the average dissipative and dipole forces acting on a A-configuration three-level atom in an arbitrary light field are derived by means of the optical Bloch equations based on the atomic density matrix elements, and the general properties of the average dissipative and dipole forces on a three-level atom in the linearly-polarized high-order Bessel beams （HBBs） are analysed. We find a resonant property （with two resonant peaks） of the dissipative force and a non-resonant property （with two pairs of non-resonant peaks） of the dipole force on the three-level atom, which are completely different from those on the two-level atom. Meanwhile we find a saturation effect of the average dissipative force in the HBB, which comes from the saturation of the upper-level population. Our study shows that the general expressions of the average dissipative and dipole forces on the three-level atom will be simplified to those of the two-level atom under the approximation of large detuning. Finally, we study the axial and azimuthal Doppler cooling of atoms in ID optical molasses composed of two counter-propagating HBBs and discuss the azimuthal influence of the HBB on the Doppler cooling limit. We also find that the Doppler limit of atoms in the molasses HBB is slightly below the conventional Doppler limit of hГ/（2kB） due to the orbital angular momentum lh of the HBB.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12064012 and 11374096)。
文摘The entropy squeezing of a V-type three-level atom interacting with a single-mode field and passing through the amplitude damping channel is investigated in detail. Our results show that when coupled to the single-mode field, the atom in appropriate initial states can not only generate obvious entropy squeezing but also keep in the optimal squeezing state,while passing through the amplitude damping channel, the atom can generate entropy squeezing under the control of the weak measurement. Besides, it is proved again that as a measurement method for atomic squeezing, the entropy squeezing is precise and effective. Therefore our work is instructive for experiments in preparing three-level system information resource with ultra-low quantum noise.
基金Project supported by the National Natural Science Foundation of China （Grant No 10374025） and by Hunan Provincial Natural Science Foundation of China （Grant No 06JJ4003）.
文摘In a system with a moving V-type three-level atom interacting with the SU（1,1）-related coherent fields, we investigate the entanglement between the moving three-level atom and the SU（1,1）-related coherent fields by using the quantum-reduced entropy, and that between the SU（1,1）-related coherent fields by using the quantum relative entropy of entanglement. It is shown that the two kinds of entanglement are dependent on the atomic motion and exhibit the periodic evolution with a period of 2π/p. The maximal atom-field qutrit entanglement state can be prepared, and the entanglement preservation of the SU（1,1）-related coherent fields can be realized in the interacting process via the appropriate selection of system parameters and interaction time.
基金Supported by Key Scientific Research Fund of Hunan Provincial Education Department of China under Grant No. 09A013Natural Science Foundation of Hunan Province of China under Grant No. 08J J3001Normal and Science Foundation of Hengyang Normal University of China under Grant No. 09A28
文摘A very simpJe theoretical scheme is proposed to implement two-and three-qubit controlled-phase gates firstly only using a single resonant interaction between ladder-type three-level atoms and the single-mode cavity. In the presented protocol, the quantum information is encoded on the stable ground states of the atoms （as the controlling qubits） and the zero- and one-photon Fock states of cavity-field （as the target qubit）. Under the influence of the atomic spontaneous emission, the decay of the cavity-mode, and deviation of the coupling strength, the three-qubit controlled- phase gate may have a comparatively high fidelity. The experimental feasibility of controlled-phase gate and the ease that is extended to realize N-qubit controlled-phase gate are also discussed.
基金Project supported by the National Natural Science Foundation of China (Grant No 10704031)the National Science Foundation for Fostering Talents in Basic Research of the National Natural Science Foundation of China (Grant No J0630313)+1 种基金the Fundamental Research Fund for Physics and Mathematics of Lanzhou University (Grant No Lzu05001)the Natural Science Foundation of Gansu Province, China (Grant No 3ZS061-A25-035)
文摘We have studied theoretically and numerically the enhanced cooling of a V-type three-level atom in a high-finesse optical cavity and shown that the cooling rate can be increased by one order of magnitude over that of a two-level atom, and the momentum amplitude tends to a stationary state much smaller than that of a two-level atom. We have further shown that the cooling rate can be significantly improved by using feedback and a time-dependent pump.
基金supported by the National Basic Research Foundation of China(Grant No.2011CB922002)
文摘Polarization, an intrinsic ingredient of photon, plays a critical role in its interaction with matter. A general polarization state can be an appropriate superposition of two basic polarization states, say, the vertical and horizontal linear polarized state. Here we study spontaneous emission of a V-type three-level atom（with two upper states close in energy level）strongly coupled with a single-mode damped optical cavity. By defining a general polarization state of atom as a specific superposition of the two upper quantum states, we can prepare atoms with linear polarization at arbitrary direction, left and right circular polarization, and left and right elliptical polarization, similar to photons. We find that the spontaneous emission of light from these ＂polarized＂ three-level atoms shows very different profiles of side and axis spectra. This means that the polarization state of three-level atoms can become an active ingredient to manipulate its interaction with light and control the quantum interference effect. Exploitation of the coherent superposition and interference of quantum states in＂polarized＂ atoms would allow one to deeply explore new frontiers of light–matter interaction.
基金Project supported by the National Natural Science Foundation of China (Grant No 10674025)the Funds from Fuzhou University
文摘This paper proposes a scheme for the generation of entangled coherent states for two cavity modes. In the scheme a V-type three-level atom is sent through a two-mode cavity filled with a coherent field. After the atom cavity interaction and detection of the atomic state the cavity modes may evolve to a superposition of two-mode coherent states. As the scheme is based on resonant atom-cavity interaction, the required interaction time is short, which is important in view of the decoherence. Moreover, additional classical pulses are unnecessary before and after the atom-cavlty interaction.
基金Project supported by the National Natural Science Foundation of China(Grant No.10704031)the National Science Foundation for Fostering Talents in Basic Research of the National Natural Science Foundation of China(Grant No.J0630313)+1 种基金the Fundamental Research Fund for Physics and Mathematics of Lanzhou University,China(Grant No.Lzu05001)the Natural Science Foundation of Gansu Province,China(Grant No.3ZS061-A25-035)
文摘A theoretical study is carried out for the modification and implication of the effect on the type three level atom in a high-finesse optical cavity driven by light field including spontaneous emission and the cavity decay. Analytic expressions for the dipole force, the friction force, the optical potentials and the friction coefficient are obtained. Then the numerical and graphical methods are used to investigate the friction coefficient with the controlling parameters. It is shown that the friction coefficient is strongly dependent on the controlling parameters. The cooling rate can increase by one order of magnitude more than that of a two-level atomic system. The reason can be given using the dressed states and the Sisyphus cooling mechanism, which would stimulate further experimental investigations.
文摘We theoretically investigate the emission spectrum for a A-type three-level atom trapped in the node of a standing wave. We show that the atomic center-of-mass motion not only directly affects the peak number, peak position, and peak height in the atomic emission spectrum, but also influences the effects of the cavity field and the atomic initial state on atomic emission spectrum.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11274148 and 10704031)the Basic Scientific Research Business Expenses of the Central University,China (Grant No. lzujbky-2010-75)the Open Project of Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education,Lanzhou University,China
文摘We study the features of electromagnetically induced transparency（EIT） in a single Λ-type three-level atom placed in a high-finesse cavity under the action of a coupling laser and a probe laser.Our calculations show that three transparency windows appear when the pump strength is large enough.This can be explained by the residual pump in the cavity mostly resulting in energy splitting.The level ｜3 is split into four slightly different energy levels,and interference takes place between the excitation pathways.Furthermore,it is also shown that the frequencies of the EIT windows can be tuned by changing the coupling field detuning 2,and that the reflection profile is very sensitive to the cavity field detuning △c.
基金The project supported by Fok Ying Tung Education Foundation under Grant No. 81008, National Natural Science Foundation of China under Grant Nos, 60008003 and 10225421, and Funds from Puzhou University
文摘A scheme is proposed for generating maximally entangled states for two or more three-level atoms. In the scheme the atoms are sent through a two-mode cavity one by one and interact with the two-cavity modes sequentially. The required experimental techniques are within the scope of what can be obtained in the microwave cavity QED setup.
基金The project supported by Fok Ying Tung Education Foundation under Grant N0. 81008, National Natural Science Foundation of China under Grant Nos. 60008003 and 10225421, and Funds from Fuzhou University
文摘A scheme is presented for generating entangled states for two three-level atoms in a cavity. In the scheme two atoms simultaneously interact with a cavity mode with a small detuning. Thus, the operation time is very short, which is important in view of decoherence.
基金The project supported by the Natural Science Foundation of Shandong Province under Grant No. Y2004A09
文摘The cavity field spectrum of a cascade three-level atom interacting with single-mode field with Kerr-like medium in the cavity is investigated. The numerical results for the initial field in pure number state, coherent state and squeezed vacuum state are calculated, respectively. It is found that the Kerr-like medium affects the spectral structure even though the initial field is in vacuum when the atom is in upper level. In the case of strong input field, the number state spectrum shows two peaks with different heights; and the superposition state spectrum shows a multipeak structure with an equal distance of two neighboring peaks. The spectral ＂central frequency＂ shifts away from the resonant frequency with the increasing of average photon number.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12064012 and 11374096)。
文摘The entropy squeezing properties of different types of moving three-level atoms coupled with a single-mode coherent field are studied. The influences of the moving velocity and initial states of the three-level atom on the entropy squeezing are discussed. The results show that, the entropy squeezing properties of the three-level atom depend on its initial state, moving velocity, and the type. A stationary three-level atom can not obtain a steady entropy squeezing whatever initial conditions are chosen, while a moving three-level atom can achieve a steady and optimal entropy squeezing through choosing higher velocity and appropriate initial state. Our result provides a simple method for preparing squeezing resources with ultra-low quantum noise of the three-level atomic system without additional any complex techniques.
基金Project supported by the National Natural Science Foundation of China(Grant No.11374096).
文摘We study the dynamics of the entropic uncertainty for three types of three-level atomic systems coupled to an environment modeled by random matrices. The results show that the entropic uncertainty in the Ξ-type atomic system is lower than that in the V-type atomic system which is exactly the same as that in the Λ-type atomic system. In addition, the effect of relative coupling strength on entropic uncertainty is opposite in Markov region and non-Markov region, and the influence of a common environment and independent environments in Markov region and non-Markov region is also opposite. One can reduce the entropic uncertainty by decreasing relative coupling strength or placing the system in two separate environments in the Markov case. In the non-Markov case, the entropic uncertainty can be reduced by increasing the relative coupling strength or by placing the system in a common environment.
文摘The Hamiltonian of coupled three-level atoms interacting with light field in the cavity filled with Kerr-like medium is derived. A simplified analytic solution to the Schrodinger equation of the system is obtained. The case of A type atom with degenerate lower levels is discussed in detail. It is shown that the coupling strength between atoms and Kerr coefficient affect the system＇s dynamic behaviors, especially the modulation period and oscillation frequency of the squeezing parameters of the field and the collective dipole moment. Dynamic behaviors of the system are sensitive to the initial state of atoms.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60378008 and 10574052.
文摘We use the relative phase difference of two bichromatic fields of equal frequency differences for the coherent control of spontaneous emission of a three-level atom in the A configuration, diffects such as selective and total cancellation of fluorescence decay are obtained simply by varying the phase difference. The phese dependence of fluorescence spectra is attributed to the fact that the four different field components induce the transitions in a closed loop configuratiou.
基金the National Fundamental Research Program under Grant No. 2006CB921106National Natural Science Foundation of China under Grant Nos. 10325521 and 60433050+1 种基金the SRFDP Program of Ministry of Education under Grant No. 20060003048the Key Project of Ministry of Education under Grant No. 306020
文摘In this paper,we present decoupling bang-bang operations for the suppression of general decoherence,bothamplitude and phase damping,in a three-level system in A-configuration.We give a program to design a sequence ofperiodic twinborn pulses to suppress the decoherence in such the system.
