利用相干量子点-腔接收器实现自旋到偏振的映射
Spin-to-polarization mapping with a coherent quantum dot-cavity receiver
- Université Paris-Saclay（巴黎萨克雷大学）
- CNRS（法国国家科学研究中心）
- Centre de Nanosciences et de Nanotechnologies（纳米科学与纳米技术中心）
- Université Paris Cité（巴黎西岱大学）
- ICFO-Institut de Ciencies Fotoniques（光子科学研究所）
- The Barcelona Institute of Science and Technology（巴塞罗那科学技术研究所）
- Quandela（量子达）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究基于带电量子点-微柱腔器件的自旋诱导克尔旋转，实现单次反射光子探测下电子自旋到偏振的95±2%保真度映射，为确定性逻辑门提供了基础。
AI中文摘要：
相干光-物质界面可通过与静止量子比特相互作用可控地改变光子状态，是实现光学量子技术确定性纠缠门的关键资源，这要求散射光子状态与内嵌量子比特状态存在一一映射关系。本研究利用低噪声带电量子点-微柱腔器件中存在的自旋诱导克尔旋转，展示了这种双射的实验特征：通过时间分辨偏振测量，在单次反射光子探测下，将电子自旋投影到其本征态之一，保真度达95±2%；并通过第二次反射光子探测跟踪后续自旋弛豫。研究表明，在激子辐射寿命主导的瞬态阶段后，可产生两个正交偏振态，分别对应给定的自旋本征态。尽管当前结果受电子自旋弛豫与激子辐射寿命之间的时间尺度竞争限制，但可利用弛豫时间更长的空穴自旋改善结果。本研究为利用自旋与散射光子偏振之间这种一一映射关系的确定性逻辑门铺平了道路。
英文摘要：
Coherent light-matter interfaces controllably modifying the state of a photon upon interaction with a stationary qubit are a key resource for implementing deterministic entangling gates for optical quantum technologies. This requires a one-to-one mapping between the state of the scattered photon and that of the embedded qubit. Here, we present an experimental signature of such a bijection by leveraging the spin-induced Kerr rotation present in a low-noise charged quantum dot-micropillar cavity device. Through time-resolved polarization measurements, we project the electron spin to one of its eigenstates with $95\pm2\%$ fidelity with a single reflected photon detection, and follow the subsequent spin relaxation through the detection of a second reflected photon. We demonstrate that, after a transient regime governed by the trion radiative lifetime, two orthogonal polarization states can be produced, each associated to a given spin eigenstate. While the current results are limited by a timescale competition between electron spin relaxation and trion radiative lifetime, they could be improved using hole spins displaying increased relaxation times. Our work paves the way towards deterministic logic gates exploiting this one-to-one mapping between a spin and the polarization of a scattered photon.
