论文标题
感冒原子在暂时多路复用的量子内存，并具有空腔增强的噪声抑制
A cold atom temporally multiplexed quantum memory with cavity-enhanced noise suppression
论文作者
论文摘要
未来的量子中继器体系结构，能够有效地分布在大距离内的量子状态下编码的信息，这将受益于多重光子量子记忆。在这项工作中，我们演示了$^{87} $ rb原子的激光冷却云中的时间多发性量子中继器节点。我们采用DLCZ协议，其中使用一系列写入脉冲在几种时间模式下创建了一对光子和单个集体自旋激发（所谓的自旋波）。为了使自旋波在不同的时间模式中产生，可以区分和启用选择性读数，我们通过磁场梯度来控制自旋波的去旋转和重塑，从而诱导了所涉及的原子高精度水平的受控可逆的不均匀宽片。我们证明，通过将原子集合嵌入低技巧的光腔内，多模式操作中产生的额外噪声得到了强烈抑制。通过使用Feed Forward读数，我们证明了多达10个时间模式的可区分检索。对于每种模式，我们证明了第一光子和第二个光子之间的非古典相关性。此外，随着我们增加存储在内存中的时间模式的数量，相关光子对的速率的提高。报告的功能是基于多路复用量子记忆的量子中继器结构的关键要素。
Future quantum repeater architectures, capable of efficiently distributing information encoded in quantum states of light over large distances, will benefit from multiplexed photonic quantum memories. In this work we demonstrate a temporally multiplexed quantum repeater node in a laser-cooled cloud of $^{87}$Rb atoms. We employ the DLCZ protocol where pairs of photons and single collective spin excitations (so called spin waves) are created in several temporal modes using a train of write pulses. To make the spin waves created in different temporal modes distinguishable and enable selective readout, we control the dephasing and rephasing of the spin waves by a magnetic field gradient, which induces a controlled reversible inhomogeneous broadening of the involved atomic hyperfine levels. We demonstrate that by embedding the atomic ensemble inside a low finesse optical cavity, the additional noise generated in multi-mode operation is strongly suppressed. By employing feed forward readout, we demonstrate distinguishable retrieval of up to 10 temporal modes. For each mode, we prove non-classical correlations between the first and second photon. Furthermore, an enhancement in rates of correlated photon pairs is observed as we increase the number of temporal modes stored in the memory. The reported capability is a key element of a quantum repeater architecture based on multiplexed quantum memories.
