论文标题
超越四级模型：量子点中的深色和热状态降解光子纠缠
Beyond the four-level model: Dark and hot states in quantum dots degrade photonic entanglement
论文作者
论文摘要
纠缠的光子对对于多种光子量子应用至关重要。迄今为止，纠缠光子的固态量子发射器最佳的是半导体量子点，该点在液态温度周围运行。为了偏爱这些来源的广泛部署，重要的是要探索和理解它们在紧凑的stirling冷却器中可访问的温度下的行为。在这里，我们研究了高达65 k的温度下的biexciton-exciton级联的光子对之间的极化纠缠。我们观察到纠缠降解以及衰减动态的变化，我们归因于热量和黑暗状态的热量和黑暗状态以及四个级别对光子对生成的生成。详细的计算考虑了其他状态和辅助转换的存在和特征支持该解释。我们希望这些结果将指导量子点的优化作为高温下高度纠缠光子的来源。
Entangled photon pairs are essential for a multitude of photonic quantum applications. To date, the best performing solid-state quantum emitters of entangled photons are semiconductor quantum dots operated around liquid-helium temperatures. To favor the widespread deployment of these sources, it is important to explore and understand their behavior at temperatures accessible with compact Stirling coolers. Here we study the polarization entanglement among photon pairs from the biexciton-exciton cascade in GaAs quantum dots at temperatures up to 65 K. We observe entanglement degradation accompanied by changes in decay dynamics, which we ascribe to thermal population and depopulation of hot and dark states in addition to the four levels relevant for photon pair generation. Detailed calculations considering the presence and characteristics of the additional states and phonon-assisted transitions support the interpretation. We expect these results to guide the optimization of quantum dots as sources of highly entangled photons at elevated temperatures.
