共查询到20条相似文献,搜索用时 15 毫秒
1.
We report on the controlled insertion of individual Cs atoms into an ultracold Rb gas at ≈400 nK. This requires one to combine
the techniques necessary for cooling, trapping and manipulating single laser cooled atoms around the Doppler temperature with
an experiment to produce ultracold degenerate quantum gases. In our approach, both systems are prepared in separated traps
and then combined. Our results pave the way for coherent interaction between a quantum gas and a single or few neutral atoms
of another species. 相似文献
2.
We show that atomic dipolar effects are detectable in the system that recently demonstrated two-atom coherent spin dynamics within individual lattice sites of a Mott state. Based on a two-state approximation for the two-atom internal states and relying on a variational approach, we have estimated the spin dipolar effect. Despite the absolute weakness of the dipole-dipole interaction, it is shown that it leads to experimentally observable effects in the spin mixing dynamics. 相似文献
3.
D. Schrader S. Kuhr W. Alt M. Müller V. Gomer D. Meschede 《Applied physics. B, Lasers and optics》2001,73(8):819-824
Using optical dipole forces we have realized controlled transport of a single or any desired small number of neutral atoms
over a distance of a centimeter with sub-micrometer precision. A standing wave dipole trap is loaded with a prescribed number
of cesium atoms from a magneto-optical trap. Mutual detuning of the counter-propagating laser beams moves the interference
pattern, allowing us to accelerate and stop the atoms at preselected points along the standing wave. The transportation efficiency
is close to 100%. This optical ‘single-atom conveyor belt’ represents a versatile tool for future experiments requiring deterministic
delivery of a prescribed number of atoms on demand.
Received: 6 July 2001 / Published online: 23 November 2001 相似文献
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实验中首先通过增大四极磁场梯度、提高背景真空度、缩小冷却俘获激光光束直径的方法获得了磁光阱中单原子的装载.其次,通过减小冷却光失谐量、适当增加其光强、同时使用偏振光谱锁频技术抑制冷却光噪声的方法得到了磁光阱中高信号背景比的单原子荧光信号.此外,通过实时反馈控制磁光阱四极磁场梯度的方法,在实验中实现了单原子98%的装载概率.使用Hamburg Brown-Twiss方案测量了磁光阱中的单原子在连续光激发下所辐射荧光的光子统计特性,得到二阶关联度g(2)(τ=0)=0.09. 相似文献
6.
Entanglement properties between two atoms in the binomial optical field interacting with two entangled atoms 下载免费PDF全文
The temporal evolution of the degree of entanglement between two atoms in a system of the binomial optical field interacting with two arbitrary entangled atoms is investigated. The influence of the strength of the dipole–dipole interaction between two atoms, probabilities of the Bernoulli trial, and particle number of the binomial optical field on the temporal evolution of the atomic entanglement are discussed. The result shows that the two atoms are always in the entanglement state. Moreover, if and only if the two atoms are initially in the maximally entangled state, the entanglement evolution is not affected by the parameters, and the degree of entanglement is always kept as 1. 相似文献
7.
Resonant two-photon single ionization in a system consisting of two spatially well-separated identical atoms is studied. Because of two-center electron-electron correlations, the ionization may also proceed through photoexcitation of both atoms with subsequent interatomic Coulombic decay. We show that this channel may qualitatively change the dependence of the photoionization on the field intensity as well as the spectra of emitted electrons. 相似文献
8.
A scheme is proposed for generating three-dimensional maximally entangled states for two atoms. In the scheme the atoms are trapped in a two-mode cavity. The scheme only requires a single resonant interaction of the atoms with the cavity modes. Therefore, the scheme is very simple and required interaction time is very short, which is important in view of decoherence. 相似文献
9.
R. Chicireanu Q. Beaufils A. Pouderous B. Laburthe-Tolra É. Maréchal L. Vernac J.-C. Keller O. Gorceix 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,45(2):189-195
We report the fast accumulation of a large number of
metastable 52Cr atoms in a mixed trap, formed by the
superposition of a strongly confining optical trap and a quadrupolar
magnetic trap. The steady state is reached after about 400 ms,
providing a cloud of more than one million metastable atoms at a
temperature of about 100 μK, with a peak density of 1018
atoms m-3. We have optimized the loading procedure, and
measured the light shift of the 5D4 state by analyzing how the
trapped atoms respond to a parametric excitation. We compare this
result to a theoretical evaluation based on the available
spectroscopic data for chromium atoms. 相似文献
10.
Collective effects in the spontaneous emission pattern of two identical two-level atoms a fixed distance apart and sharing initially a single excitation are investigated. It is shown that the interference can take place even when it is known for certain which atom is excited initially. This interference is due solely to the atomic coherence established through multiple photon absorptions and reemissions and will disappear if it is ignored. The interference patterns with and without collective effects are compared for symmetric and antisymmetric initial states. The dark center from an antisymmetric state is shown both analytically and numerically. 相似文献
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McKeever J Buck JR Boozer AD Kuzmich A Nägerl HC Stamper-Kurn DM Kimble HJ 《Physical review letters》2003,90(13):133602
Single cesium atoms are cooled and trapped inside a small optical cavity by way of a novel far-off-resonance dipole-force trap, with observed lifetimes of 2-3 s. Trapped atoms are observed continuously via transmission of a strongly coupled probe beam, with individual events lasting approximately 1 s. The loss of successive atoms from the trap N>/=3-->2-->1-->0 is thereby monitored in real time. Trapping, cooling, and interactions with strong coupling are enabled by the trap potential, for which the center-of-mass motion is only weakly dependent on the atom's internal state. 相似文献
13.
Yu-chi Zhang Gang Li Peng-fei Zhang Jun-min Wang Tian-cai Zhang 《Frontiers of Physics in China》2009,4(2):190-197
Cavity QED, as a fundamental system and research field, not only illuminates the primary aspects of decoherence and coherence
in quantum dynamics, but also advances quantum information science. Manipulation of single atoms, in the context of cavity
QED, is the essential element and has been becoming a hot issue for the past two decades. In this review paper, we will concentrate
on the experimental aspects for manipulating the neutral atoms strongly coupled to a high-finesse cavity in the optical regime,
including atomic cooling and trapping, different configurations of atom transportation and the wide variety of quantum outgrowths
based on cavity QED, such as one atom laser, single photon source, etc. The cavity QED system at Shanxi University is briefly
introduced.
相似文献
14.
C. X. Zhang B. Zhou Y. H. Nie J. Q. Liang J. Liu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,49(2):161-165
We study the transport of atoms across a localized Bose-Einstein condensate in an onedimensional optical lattice with a single
defect. Our analytical and numerical results show that the defect as well as the nonlinear parameter can control the transmission
of the atoms beam and the position of total reflection caused by Fano resonance. These interesting features may be a very
useful basis for devising tunable atom filters or a button. 相似文献
15.
A highly efficient summing of mutually coherent beams (channels) into a single beam with the same divergence and aperture (an inverse acoustooptic problem) is realized via diffraction in a Bragg cell. The multibeam field to be converged is formed as a result of the diffraction (splitting) of a single laser beam. Theoretical and experimental evidence is obtained for the fact that the repeated diffraction can provide a highly efficient (up to 100%) reconstruction of beam with initial parameters. The experiments are performed with a single-mode laser radiation at 0.63 μm and multimode radiation at 0.96 μm. The virtually attained summing efficiency is on the order of 70%. The factors that act to diminish the experimental efficiency below the predicted value, the ways to raise the efficiency, and possible applications of the results of this study are discussed. 相似文献
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We demonstrate a method to count small numbers of atoms held in a deep, microscopic optical dipole trap by collecting fluorescence from atoms exposed to a standing wave of light that is blue detuned from resonance. While scattering photons, the atoms are cooled by a Sisyphus mechanism that results from the spatial variation in light intensity. The use of a small blue detuning limits the losses due to light-assisted collisions, thereby making the method suitable for counting several atoms in a microscopic volume. 相似文献
18.
H. Prakash R. Kumar 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(3):475-481
Saito and Ueda [Phys. Rev. A 59, 3959 (1999)] studied atomic and
radiation squeezing in interaction of a single mode coherent state
of radiation with two excited two-level atoms, using
the Jaynes Cummings Hamiltonian. They considered α real and studied
squeezing of the Dicke operator Sx using the Kitagawa-Ueda criterion for
squeezing and coupling times less than or nearly equal to
. We obtain results to all orders in coupling time for
atoms, which are initially in (i) fully excited, (ii) superradiant or in
(iii) ground states and obtain more general results. We use our recently
reported criterion for atomic squeezing, of which the Kitagawa-Ueda
criterion is a special case, and obtain a much stronger (nearly 95%)
atomic squeezing than that (nearly 1.1%) reported by Saito and Ueda. 相似文献
19.
Entanglement of two distinguishable atoms in a rectangular waveguide: Linear approximation with single excitation 下载免费PDF全文
《中国物理 B》2021,30(9):90307-090307
We investigate the entanglement dynamics of two distinguishable two-level systems(TLSs) characterized by energy difference δ located inside a rectangular hollow metallic waveguide of transverse dimensions a and b. The effects of energy difference δ and the inter-TLS distance on the time evolution of the concurrence of the TLSs are examined in the single excitation subspace when the energy separation of the TLS is far away from the cutoff frequencies of the transverse mode. 相似文献
20.
A single atom in a magneto–optical trap(MOT) with trap size(hundreds of micrometers) can be transferred into an optical microscopic tweezer with a probability of ~100%. The ability to transfer a single atom into two traps back and forth allows us to study the loading process. The loading probability is found to be insensitive to the geometric overlap of the MOT and the tweezer. It is therefore possible to perform simultaneously loading of a single atom into all sites of the tweezer array for many qubits. In particular, we present a simulation of the one-dimensional and two-dimensional arrays of an optical microscopic tweezer. We find the same qualitative behavior for all of the trap parameters. 相似文献