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arXiv 1605.03429quant-phphysics.optics
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千兆赫带宽的高斯纠缠分布

Gaussian entanglement distribution with gigahertz bandwidth

Stefan Ast, Melanie Ast, Moritz Mehmet, Roman Schnabel

摘要:

利用高斯统计量的纠缠分布可以产生一个量子密码学上可证明的安全密钥。分布式密钥速率受纠缠强度、纠缠带宽和光电探测器带宽的限制。开发一种高带宽的强二分纠缠光源,可以提高测量速度,并线性提高安全数据速率。本文介绍了一个带宽大于1.25GHz的高斯纠缠源的实验实现.利用平衡零差探测器测量了纠缠谱,并通过Duan及其同事引入的不可分性标准进行了量化,临界值为4,低于该临界值时,纠缠被证明是有效的。我们的测量得到的不可分性值在300MHz处约为1.8,在1.2GHz处约为2.8,进一步扩展到1.48GHz处约为3.1。实验中使用两个2.6mm长的周期极化磷酸钛氧钾(PPKTP)谐振腔,在1550nm的通信波长处产生两个压缩光场。我们的结果证明了高速产生和探测强连续变量纠缠的可能性。

英文摘要:

The distribution of entanglement with Gaussian statistic can be used to generate a mathematically-proven secure key for quantum cryptography. The distributed secret key rate is limited by the {entanglement strength, the entanglement bandwidth and the bandwidth of the photo-electric detectors}. The development of a source for strongly, bi-partite entangled light with high bandwidth promises an increased measurement speed and a linear boost in the secure data rate. Here, we present the experimental realization of a Gaussian entanglement source with a bandwidth of more than 1.25\,GHz. The entanglement spectrum was measured with balanced homodyne detectors and was quantified via the inseparability criterion introduced by Duan and coworkers with a critical value of 4 below which entanglement is certified. Our measurements yielded an inseparability value of about 1.8 at a frequency of 300\,MHz to about 2.8 at 1.2\,GHz extending further to about 3.1 at 1.48\,GHz. In the experiment we used two 2.6\,mm long monolithic periodically poled potassium titanyl phosphate (PPKTP) resonators to generate two squeezed fields at the telecommunication wavelength of 1550\,nm. Our result proves the possibility of generating and detecting strong continuous-variable entanglement with high speed.

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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