作者：
Sun, Li-Hui;Li, Gao-xiang;Gu, Wen-Ju;Ficek, Zbigniew
期刊：
Optics InfoBase Conference Papers,2012年
通讯作者：
Ficek, Z.(zficek@kacst.edu.sa)
作者机构：
[Li, Gao-xiang; Gu, Wen-Ju; Sun, Li-Hui] Department of Physics, Huazhong Normal University, Wuhan 430079, China;[Ficek, Zbigniew] The National Centre for Mathematics and Physics, KACST, P.O. Box 6086, Riyadh 11442, Saudi Arabia;[Sun, Li-Hui] College of Physical Science and Technology, Yangtze University, Jingzhou, Hubei 434023, China
会议名称：
International Conference on Ultrafast Structural Dynamics
会议时间：
19–21 March 2012
会议地点：
Berlin Germany
会议论文集名称：
International Conference on Ultrafast Structural Dynamics
摘要：
The spontaneous emission properties of a two-level emitter embedded in a negative permeability slab near the interface between a negative permeability slab and a negative permittivity slab are investigated. When the impedances of the two slabs are matched and the dissipation of the material is small, the structure forms a very good single-mode cavity for surface plasmons. The extremely high local density of states of surface plasmons results in ultrastrong coupling between the atom and the surface plasmons, and then large vacuum Rabi frequency. A damped vacuum Rabi oscillation occurs in the dynamic evolution of the excited atom close to the interface. The atomic emission spectrum displays an asymmetric two-peak structure with the peak separation equal to the vacuum Rabi frequency.
作者机构：
[Yi, Zhen; Li, Gao-xiang; Gu, Wen-ju] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Yi, Zhen] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
摘要：
We propose a cooling scheme for the V-type three-level atom tightly confined in a harmonic trap. Two excited levels are coupled to the ground state by a quadrupole transition with a small dissipation rate and a dipole transition with a large dissipation rate, respectively. The quadrupole transition is strongly driven by a running-wave laser 1, which acts as the cooling channel in the Lamb-Dicke regime. The dipole one is weakly driven by another running-wave laser 2 as the auxiliary transition. Ground-state cooling with a large rate can be achieved through the appropriate choice of Rabi frequency for laser 1 and the detuning of the auxiliary transition.
作者机构：
[Zhu, Jia-pei; Li, Gao-xiang] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Zhu, Jia-pei] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
摘要：
We employ double quantum interference to propose a ground-state cooling scheme for a nanomechanical resonator coupled to a triple quantum dot (TQD), of which the third dot is driven by a microwave field. In our scheme, the carrier transition is diminished by the destructive interference (the occurrence of a dark state) arising from the coherent tunnelings of electrons among the three dots. Furthermore, the additional transition induced by the microwave field enables the system to possess double quantum interference effect. Under certain conditions, the processes which might increase one phonon through the blue sideband transitions are prohibited due to the double destructive interference analog to double electromagnetically induced transparency mechanism. Thus, both the carrier and blue sideband transitions are canceled. The cooling process occurs when the electron trapped in the dark state absorbs one phonon of the resonator through the transition from the dark state to the bright state and then to the excited state and finally tunnels to the drain. As a result, the phonon occupation can be reduced to zero in the ideal case and the resonator can be cooled down to its ground state with high efficiency even when the dephasing of the TQD is present.
作者机构：
[Li, Gao-xiang; Gu, Wen-ju] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Gu, Wen-ju] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
摘要：
The non-Markovian behavior of a V-type three-level atom coupled to a zero-temperature bosonic Lorentzian reservoir is investigated. The two decay channels from two upper states to the ground one are connected due to the spontaneously generated interference. When the two upper states are degenerate, the two channels can be decoupled, and an analytical lower bound of the non-Markovian behavior can be obtained by the optimal choice of a pair of initial states. The non-Markovian behavior can be enhanced by the interference.
摘要：
A scheme for ground-state cooling of a mechanical resonator by single- and two-phonon processes is analyzed. The mechanical resonator is coupled to two coupled quantum dots forming an effective Λ-type three-level structure and connected with two normal metal leads. The quantum dots are driven by two light fields; by choosing appropriate parameters, the electron can be trapped in the dark state of the system, a superposition of the two ground states. When the single-phonon absorption and emission processes are dominant, under the weak (strong) driving field circumstances, the mechanical resonator is cooled through absorbing a phonon when the electron jumps from dark state to bright state (one of the dressed states) and then tunnels out of the two coupled dots. Net cooling of the resonator to its ground state is possible in the absence of the electron-phonon dephasing via single-phonon processes. When the two-phonon processes are tuned to be stronger than the single-phonon processes, the mechanical resonator can be cooled to its nonclassical state.
作者机构：
[Zhu, Jia-pei; Li, Gao-xiang] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.;[Ficek, Zbigniew] KACST, Natl Ctr Math & Phys, Riyadh 11442, Saudi Arabia.
通讯机构：
[Zhu, Jia-pei] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
摘要：
The steady-state cooling of a nanomechanical resonator interacting with three coupled quantum dots is studied. General conditions for the cooling to the ground state with single- and two-electron dark states are obtained. The results show that in the case of the interaction of the resonator with a single-electron dark state, no cooling of the resonator occurs unless the quantum dots are not identical. The steady-state cooling is possible only if the energy state of the quantum dot coupled to the drain electrode is detuned from the energy states of the dots coupled to the electron source electrode. The detuning has the effect of unequal shifting of the effective dressed states of the system in which the cooling and heating processes occur at different frequencies. For the case of two electrons injected to the quantum-dot system, the creation of a two-particle dark state is established to be possible with spin-antiparallel electrons. The results predict that with the two-particle dark state, an effective cooling can be achieved even with identical quantum dots subject to an asymmetry only in the charging potential energies coupling the injected electrons. It is found that, similar to the case of the single-electron dark state, the asymmetries result in the cooling and heating processes occurring at different frequencies. However, an important difference between the single- and two-particle dark-state cases is that the cooling process occurs at significantly different frequencies. This indicates that the frequency at which the resonator could be cooled to its ground state can be changed by switching from the one-electron to the two-electron Coulomb blockade process.
作者机构：
[Zhou Ben-Yuan; Yu Li; Deng Lei; Duan Yong-Fa] AF Early Warning Acad, Basic Course Dept, Phys Teaching Sect, Wuhan 430019, Peoples R China.;[Li Gao-Xiang] Cent China Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Zhou Ben-Yuan] A;AF Early Warning Acad, Basic Course Dept, Phys Teaching Sect, Wuhan 430019, Peoples R China.
关键词：
quantum nonlocality;photon addition;squeezed entangled coherent states
摘要：
Effects of photon addition on the quantum nonlocality of squeezed entangled coherent states for Bell-inequality tests are studied theoretically. By utilizing the method of photon-parity measurement, it is found that photon addition can always increase the degrees of Bell violations within a certain parameter range. A possible scheme for generating photon-added squeezed entangled coherent states is proposed.
作者机构：
[Li, Gao-xiang; Sun, Li-hui] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.;[Sun, Li-hui] Yangtze Univ, Coll Phys Sci & Technol, Jinzhou 434023, Peoples R China.;[Ficek, Zbigniew] KACST, Natl Ctr Math & Phys, Riyadh 11442, Saudi Arabia.
通讯机构：
[Sun, Li-hui] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
摘要：
The coherence and correlation properties of effective bosonic modes of a nanomechanical cavity composed of an oscillating mirror and containing an optical lattice of regularly trapped atoms are studied. The system is modeled as a three-mode system: two orthogonal polariton modes, representing the coupled optical lattice and the cavity mode, and one mechanical mode, representing the oscillating mirror. We examine separately the cases of two-mode and three-mode interactions, which are distinguished by suitable tuning of the mechanical mode to the polariton mode frequencies. In the two-mode case, we find that the occurrence of entanglement in the system is highly sensitive to the presence of first-order coherence between the modes. In particular, the creation of the first-order coherence among the polariton and mechanical modes is achieved at the expense of entanglement between them. In the three-mode case, we show that no entanglement is created between the independent polariton modes if both modes are coupled to the mechanical mode by the parametric interaction. There is no entanglement between the polaritons even if the oscillating mirror is damped by a squeezed vacuum field. The interaction creates first-order coherence between the polaritons, and the degree of coherence can, in principle, be as large as unity. This demonstrates that the oscillating mirror can establish first-order coherence between two independent thermal modes. Further analysis shows that two independent thermal modes can be made entangled in the system only when one of the modes is coupled to the intermediate mode by a parametric interaction and the other is coupled by a linear-mixing interaction.
作者机构：
[Li, Gao-xiang; Sun, Li-hui] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.;[Sun, Li-hui] Yangtze Univ, Coll Phys Sci & Technol, Jinzhou 434023, Peoples R China.
通讯机构：
[Sun, Li-hui] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
摘要：
We propose a scheme to generate four-mode cluster states with four atomic ensembles trapped in single-mode cavities connected by short fibers. With the aid of the cavity dissipation, we find that a four-mode cluster state can be unconditionally created by the simultaneous driving of the ensembles with laser pulses of suitably chosen Rabi frequencies and phases. The scheme could be easily extended to the case of N-mode cluster states.
作者机构：
[Li, Gao-xiang] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.;[Ficek, Zbigniew] KACST, Natl Ctr Math & Phys, Riyadh 11442, Saudi Arabia.
通讯机构：
[Li, Gao-xiang] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
会议名称：
10th International Conference on Quantum Communication, Measurement and Computing (QCMC)
会议时间：
JUL 19-23, 2010
会议地点：
Brisbane, AUSTRALIA
会议主办单位：
[Li, Gao-xiang] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.^[Ficek, Zbigniew] KACST, Natl Ctr Math & Phys, Riyadh 11442, Saudi Arabia.
会议论文集名称：
AIP Conference Proceedings
关键词：
quantum electrodynamics, Stark effect, photon counting, mathematical operators
摘要：
We study the problem of creation of multi-mode continuous variable entangled states in an atomic ensemble located inside a high-Q ring cavity composed of two degenerate mutually counter-propagating modes. We show that multi-mode squeezed (entangled) states can be constructed from the vacuum by a unitary transformation associated with the collective dynamics of the atomic ensemble subjected to external lasers pulses of suitably adjusted amplitudes and phases.
