Entangling Many Atomic Ensembles through Laser Manipulation

Abstract

We propose an experimentally feasible scheme to generate the Greenberger-Horne-Zeilinger-type of maximal entanglement between many atomic ensembles based on laser manipulation and single-photon detection. The scheme, with inherent fault tolerance to the dominant noise and efficient scaling of the efficiency with the number of ensembles, allows one to maximally entangle many atomic ensembles within the reach of current technology. Such a maximum entanglement of many ensembles has wide applications in the demonstration of quantum nonlocality, high-precision spectroscopy, and quantum information processing.

Combinatorics and Quantum Nonlocality

“…For example, for n = 8, η * ≤ 0.46 and R pub ≥ 9 bits, and for n = 12, η * ≤ 0.29 and R pub ≥ 22 bits. Therefore it should be feasible to realize experimentally the states and measurements required for these tests of quantum nonlocality, using either extensions of the techniques above, ion traps [17] (up to four ions have been entangled), or atomic ensembles following a recent proposal [18]. However, in experiments noise is inevitable, whereas we have considered here only noiseless correlations.…”

Engineering an interaction and entanglement between distant atoms

“…Numerous proposals have been made for entangling atoms trapped in distinct cavities [2,3,4,5,6,7,8,9,10,11,12,13]. Such atomic entanglement would be necessary to test Bell's inequalities and quantum communication protocols with well separated massive particles.…”

Generation of cluster states

“…Firstly, atomic ensembles 1 and 2 can be prepared in the state |φ [18]. Then we can omit e iϕ by the way in [19] and perform a single-qubit rotation on atomic ensemble 2. The state of atomic ensembles 1 and 2 becomes |φ 12 = (h…”

“…Tripartite GHZ states can be prepared using the protocol of Ref [19] with atomic ensembles. Firstly, atomic ensembles 1 and 2 can be prepared in the state |φ [18].…”

“…In addition, atomic ensembles with suitable level structure could have some kinds of collectively enhanced coupling to certain optical mode due to the multi-atom interference effects. Due to the above distinct advantages, a lot of novel schemes for the generation of quantum entangled states and quantum information processing have been proposed by using atomic ensembles [19,20,21,22,23]. Thus in this paper, we propose two schemes for the generation of the cluster states using cavity QED technique and the atomic ensembles.…”