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arXiv quant-ph/0511237quant-ph
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对称Dicke态附近多体纠缠的探测

Detection of multipartite entanglement in the vicinity of symmetric Dicke states

Geza Toth

摘要:

我们提出了检测对称Dicke态纠缠的方法。特别地,我们考虑了具有N/2个激发的N-量子比特对称Dicke态。在论文的第一部分中,我们表明,对于大N,这些状态与没有真正多体纠缠的状态具有最小的重叠。因此,这些态特别适合于多体纠缠的实验研究。我们提出了基于量子态的纠缠见证算子来检测这些态周围的多体纠缠。在本文的第二部分中,我们考虑纠缠标准,有点类似于自旋压缩标准,基于集体自旋算符的矩或方差。令人惊讶的是,这些标准是基于可分离状态的方差上限。我们提出的标准检测纠缠一般和标准检测只有真正的多体纠缠。根据我们的标准测量的集体算符是一个重要的物理量:它的期望值基本上给出了相干原子云发光时的辐射强度。

英文摘要:

We present methods for detecting entanglement around symmetric Dicke states. In particular, we consider N-qubit symmetric Dicke states with N/2 excitations. In the first part of the paper we show that for large N these states have the smallest overlap possible with states without genuine multi-partite entanglement. Thus these states are particulary well suited for the experimental examination of multi-partite entanglement. We present fidelity-based entanglement witness operators for detecting multipartite entanglement around these states. In the second part of the paper we consider entanglement criteria, somewhat similar to the spin squeezing criterion, based on the moments or variances of the collective spin operators. Surprisingly, these criteria are based on an upper bound for variances for separable states. We present both criteria detecting entanglement in general and criteria detecting only genuine multi-partite entanglement. The collective operator measured for our criteria is an important physical quantity: Its expectation value essentially gives the intensity of the radiation when a coherent atomic cloud emits light.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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