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1.
It is shown in numerical simulations with two-level atoms moving through a single-mode high-Q cavity that spontaneous emission of a new type — chaotic Rabi vacuum oscillations — arises in the strong atom-field coupling
regime.
Pis’ma Zh. éksp. Teor. Fiz. 65, No. 11, 801–806 (10 June 1997) 相似文献
2.
We investigate the entanglement between two atoms in an overdamped cavity injected with squeezed vacuum when these two atoms are initially prepared in coherent states. It is shown that the stationary entanglement exhibits a strong dependence on the initial state of the two atoms when the spontaneous emission rate of each atom is equal to the collective spontaneous emission rate, corresponding to the case where the two atoms are close together. It is found that the stationary entanglement of two atoms increases with decreasing effective atomic cooperativity parameter. The squeezed vacuum can enhance the entanglement of two atoms when the atoms are initially in coherent states. Valuably, this provides us with a feasible way to manipulate and control the entanglement, by changing the relative phases and the amplitudes of the polarized atoms and by varying the effective atomic cooperativity parameter of the system, even though the cavity is a bad one. When the spontaneous emission rate of each atom is not equal to the collective spontaneous emission rate, the steady-state entanglement of two atoms always maintains the same value, as the amplitudes of the polarized atoms varies. Moreover, the larger the degree of two-photon correlation, the stronger the steady-state entanglement between the atoms. 相似文献
3.
Serge Haroche 《Hyperfine Interactions》1998,114(1-4):87-101
A Rydberg atom coupled to a single field mode in a high Q superconducting cavity is an ideal tool to perform experiments testing the most puzzling aspects of the quantum theory. The coupling between the atom and the field is either resonant or dispersive. In the resonant case, quantum Rabi oscillations in the vacuum or in a small coherent field injected in the cavity are observed. The analysis of these signals reveals in a striking way the quantization of the field. Quantum Rabi oscillations are also used to produce entanglement between successive atoms crossing the cavity. Dispersive atom-field coupling is used to prepare coherent superpositions of field states with different phases (Schrödinger cat states). The progressive decoherence of these states is studied by measuring correlations between the energies of pairs of atoms sent through the cavity with a variable delay between them. These experiments provide fundamental tests of quantum theory and shed light on the transition from quantum to classical in mesoscopic systems. 相似文献
4.
Hughes S 《Physical review letters》2005,94(22):227402
The modified spontaneous emission dynamics of two photon-coupled quantum dots in a planar-photonic crystal are theoretically investigated. Based on a photon Green function technique for quantizing the electromagnetic fields in arbitrary surroundings, pronounced vacuum Rabi oscillations and dipole-dipole interactions are self-consistently incorporated and are shown to result in a high degree of quantum-bit entanglement. Quantum dots with different optical dipole moments are also found to yield a very rich display of quantum dynamics and offer several advantages over coupling identical atoms. 相似文献
5.
Hughes S 《Optics letters》2005,30(11):1393-1395
A theoretical quantum-optical study of the modified spontaneous emission dynamics from a single quantum dot in a photonic crystal nanocavity is presented. By use of a photon Green function technique, enhanced single-photon emission and pronounced vacuum Rabi flops are demonstrated, in qualitative agreement with recent experiments. 相似文献
6.
We propose a method of generating multipartite entanglement by considering the interaction of a system of N two-level atoms in a cavity of high quality factor with a strong classical driving field. It is shown that, with a judicious choice of the cavity detuning and the applied coherent field detuning, vacuum Rabi coupling produces a large number of important multipartite entangled states. It is even possible to produce entangled states involving different cavity modes. Tuning of parameters also permits us to switch from Jaynes-Cummings to anti-Jaynes-Cummings-like interaction. 相似文献
7.
Prants SV Kon'kov LE Kirilyuk IL 《Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics》1999,60(1):335-346
The dynamics of an ensemble of two-level atoms moving through a single-mode lossless cavity is investigated in the semiclassical and rotating-wave approximations. The dynamical system for the expectation values of the atomic and field observables is considered as a perturbation to one of the following integrable versions: (i) a model with atoms moving through a spatially inhomogeneous resonant field, and (ii) a model with atoms interacting with a nonresonant eigenmode which is assumed to be homogeneous on the cavity size. We find the general exact solutions for both the models and show that they contain special solutions describing a coherent effect of population and radiation trapping. Using the Melnikov method, we prove analytically transverse intersections of stable and unstable manifolds of a hyperbolic fixed point under a small modulation of the vacuum Rabi frequency. These intersections are believed to provide the Smale horseshoe mechanism of Hamiltonian chaos. The analytical results are accompanied with direct computation of topographical maps of maximal Lyapunov exponents that give a representative image of regularity and chaos in the atom-field system in different ranges of its control parameters--the frequency detuning, the number, and the velocity of atoms. 相似文献
8.
Edda Wehner Raffaella Seno Nicoletta Sterpi Berthold-Georg Englert Herbert Walther 《Optics Communications》1994,110(5-6):655-669
Although in standard micromaser experiments the collective events, in which two or more atoms are inside the resonator at one time, are very rare, they may cause dramatic effects nevertheless. We find in particular that the so-called “trapped vacuum state” (in which single atoms would undergo a complete Rabi cycle while traversing the cavity and emerge without having emitted a photon) is destroyed even when more than 99% of the atoms participate in one-atom events. 相似文献
9.
A quantum mechanical superposition of a long-lived, localized phonon and a matter excitation is described. We identify a realization in strained silicon: a low-lying donor transition (P or Li) driven solely by acoustic phonons at wavelengths where high-Q phonon cavities can be built. This phonon-matter resonance is shown to enter the strongly coupled regime where the "vacuum" Rabi frequency exceeds the spontaneous phonon emission into noncavity modes, phonon leakage from the cavity, and phonon anharmonicity and scattering. We introduce a micropillar distributed Bragg reflector Si/Ge cavity, where Q?10(5)-10(6) and mode volumes V?25λ(3) are reachable. These results indicate that single or many-body devices based on these systems are experimentally realizable. 相似文献
10.
The realization of the strong coupling regime is requisite for implementing quantum information tasks. Here, a method for enhancing the atom–field coupling in highly dissipative coupled cavities is proposed. By introducing parametric squeezing into the primary cavity, which is only virtually excited under specific parametric conditions, coupling enhancement between the atom and the auxiliary cavity is realized for appropriate squeezing parameters. This enables the system to be robust against large cavity decay and atomic spontaneous emission. The observation of vacuum Rabi oscillations show that the originally weakly coupled system can be enhanced into an effective strong coupling regime. 相似文献
11.
Yan ZhangYu Zhang Xiao-Hang ZhangMiao Yu Cui-Li CuiJin-Hui Wu 《Physics letters. A》2012,376(4):656-661
We study the dynamic processes of reversible light storage in a double-Λ system of cold atoms by modulating two counter-propagating control fields in three successive stages. We find that stationary light pulses (SLPs) can be generated when we switch on both control fields to retrieve the stored light signal from a wave-packet of atomic spin coherence. But the two control fields should have equal Rabi frequencies for a symmetric structure of atomic levels while unequal Rabi frequencies for an asymmetric structure of atomic levels. That is, the generation of SLPs requires a special ratio between Rabi frequencies of the two control fields, which is determined by the spontaneous decay rates of relevant atomic transitions. We also show that phase modulation and profile reversal of the released light signal can be implemented by suitably manipulating the two control fields. The double-Λ system of cold atoms has the advantage of high efficiency and high fidelity, when compared to the Λ system of cold atoms, because SLPs generated therein suffer very slow decay and diffusion. 相似文献
12.
耦合双原子Jaynes-Cummings模型的腔场谱H 总被引:14,自引:8,他引:6
研究了处于激发态的两原子与高Q腔场相互作用单光子过程的腔场谱,给出了初始光场为光子数态、相干态、压缩真空态时的腔场谱数值计算结果,分析了原子间偶极-偶极相互作用强度gα对腔场谱结构的影响.发现真空场Rabi峰,当gα较弱时为4峰,gα较强时为3峰结构;弱场数态(n>0)时为5峰,强场时为3峰结构.相干态和压缩真空态时,谱结构与光子数分布有关,一般为复杂的多峰结构.结果表明,gα对峰位峰高都有影响,破坏了谱结构的对称性,但这种影响只在真空场和弱场时才较明显. 相似文献
13.
Stationary entanglement between two spatially separated atoms driven by a coherent laser field
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This paper studies quantum entanglement between two spatially
separated atoms driven by a coherent laser field in the dissipative
process of spontaneous emission. It is shown that the entanglement
strongly depends on the detuning of the laser frequency from atomic
transition frequency, the interatomic separation and the Rabi
frequency of the coherent laser field. A considerable amount of
steady state entanglement can be obtained near Δ=-α
(i.e., the dipole--dipole interaction and the detuning cancel out
mutually) for small atomic separation and large Rabi frequency of
the coherent laser field. 相似文献
14.
We investigate photon-number dependent cavity vacuum induced transparency and magneto-optical rotation (MOR) in a cavity quantum electrodynamics system, which consists of two cavities and an ensemble of Λ-type atoms. We demonstrate that the probe photon coupled into one cavity can be transferred to the mode of another cavity via coherent Raman scattering. The transmission, the phase shift, as well as the vacuum Rabi splitting therefore strongly depend upon the probe photon number coupled into the cavity. The photon number dependent cavity vacuum induced transparency can be extended into four-level tripod atoms, leading to photon-number dependent MOR. This can be used to separate the single photon from higher photon number components in the direction of polarization and create a deterministic single photon source. 相似文献
15.
16.
研究了基于腔量子电动力学(腔QED)系统的几何量子失谐及其传送。该系统包括两个独立的子系统,每个子系统由两个二能级原子与单模腔共振相互作用。结果表明,所有初始存储在原子A1A2中的几何量子失谐最终被转移到原子B1B2和腔C1C2。同时,原子A1A2 ,B1B2和腔C1C2的几何量子失谐在该量子系统中可以发生猝死(DSD)以及纠缠突然死亡(ESD)。但是,在该量子系统中几何量子失谐不能完全由于原子的自发辐射和腔衰减而复活。此外,原子A1A2 ,B1B2和腔C1C2几何量子失谐的量,取决于其纯度p,并与其成比例,p的值越小,几何失谐越小。它也表明,在原子自发辐射和腔衰减的情况下,原子A1A2 ,B1B2和腔C1C2的几何量子失谐将经历振荡衰减并最终衰减到零。不过,在没有原子自发辐射和腔衰减的情况下,原子A1A2 ,B1B2和腔C1C2的几何量子失谐却没有衰减。 相似文献
17.
研究了基于腔量子电动力学(腔QED)系统的几何量子失谐及其传送。该系统包括两个独立的子系统,每个子系统由两个二能级原子与单模腔共振相互作用。结果表明,所有初始存储在原子A1A2中的几何量子失谐最终被转移到原子B1B2和腔C1C2。同时,原子A1A2 ,B1B2和腔C1C2的几何量子失谐在该量子系统中可以发生猝死(DSD)以及纠缠突然死亡(ESD)。但是,在该量子系统中几何量子失谐不能完全由于原子的自发辐射和腔衰减而复活。此外,原子A1A2 ,B1B2和腔C1C2几何量子失谐的量,取决于其纯度p,并与其成比例,p的值越小,几何失谐越小。它也表明,在原子自发辐射和腔衰减的情况下,原子A1A2 ,B1B2和腔C1C2的几何量子失谐将经历振荡衰减并最终衰减到零。不过,在没有原子自发辐射和腔衰减的情况下,原子A1A2 ,B1B2和腔C1C2的几何量子失谐却没有衰减。 相似文献
18.
An efficient scheme is proposed for the generation of atomic Schrodinger cat states in an optical cavity. Inthe scheme N three-level atoms are loaded in the optical cavity. Raman coupling of two ground states is achieved via alaser field and the cavity mode. The cavity mode is always in the vacuum state and the atoms have no probability ofbeing populated in the excited state. Thus, the scheme is insensitive to both the cavity decay and spontaneous emission. 相似文献
19.
We propose the methods of generating multipartite entanglement by considering the interaction of a system of N two-level atoms in M cavities of high quality factor with a strong classical driving field. It is shown that, with the cavity detuning, the applied driving field detuning and vacuum Rabi coupling, we can produce an entangled coherent state in two single-mode cavities and generate the entangled coherent cluster states in two bimodal vacuum cavities. Tuning these parameters also allows us to acquire the anti-Jaynes-Cummings (AJC) interaction, with which we can generate the maximally two-photon entangled states, and the two-atom and the two-photon entangled cluster states. 相似文献
20.
ZHENGShi-Biao LINLi-Hua JIANGYun-Kun 《理论物理通讯》2003,40(1):103-104
An efficient scheme is proposed for the generation of atomic Schroedinger cat states in an optical cavity. In the scheme N three-level atoms are loaded in the optical cavity. Raman coupling of two ground states is achieved via a laser tield and the cavity mode. The cavity mode is always in the vacuum state and the atoms have no probability of being populated in the excited state. Thus, the scheme is insensitive to both the cavity decay and spontaneous emission. 相似文献