Measuring multipartite entanglement through dynamic susceptibilities
Measuring multipartite entanglement through dynamic susceptibilities
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DOI：
10.1038/nphys3700
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发表时间：
2016-08-01
期刊：
影响因子：
19.6
通讯作者：
Zoller, Peter
中科院分区：
文献类型：
--
作者：
Hauke, Philipp;Heyl, Markus;Zoller, Peter
纠缠被认为是量子技术的重要资源，也是理解量子多体物理的核心。因此，开发检测和量化多粒子量子态纠缠的协议是当前实验的关键挑战。在这里，我们表明，量子费雪信息，一个真正的多部纠缠的见证，可以通过动态磁化率来测量热系综，即利用目前冷原子-气体和凝聚态实验中现成的资源。这建立了多方纠缠和响应函数中包含的多体关联之间的联系，具有接近量子相变的直接含义，其中量子Fisher信息变得普遍，使我们能够识别具有发散多方纠缠的强纠缠相变。我们使用聚合量子lsing模型说明了我们的框架，并指出了光晶格实验和强相关材料中的潜在特征。
Entanglement is considered an essential resource in quantum technologies, and central to the understanding of quantum many body physics. Developing protocols to detect and quantify the entanglement of many-particle quantum states is thus a key challenge for present experiments. Here, we show that the quantum Fisher information, a witness for genuinely multipartite entanglement, becomes measurable for thermal ensembles by means of the dynamic susceptibility that is, with resources readily available in present cold atomic-gas and condensed-matter experiments. This establishes a connection between multipartite entanglement and many-body correlations contained in response functions, with immediate implications close to quantum phase transitions, where the quantum Fisher information becomes universal, allowing us to identify strongly entangled phase transitions with a divergent multipartite entanglement. We illustrate our framework using paradigmatic quantum lsing models, and point out potential signatures in optical-lattice experiments and strongly correlated materials.