论文标题
通过声音辅助激发探测半导体孔自旋的动力学和相干性
Probing the dynamics and coherence of a semiconductor hole spin via acoustic phonon-assisted excitation
论文作者
论文摘要
如在开创性的鲁道夫 - 林德纳方案中提出的那样，半导体量子点中的旋转是有希望的局部量子记忆，以产生极化编码的光子簇状态[1]。然而，利用光学转变的极化程度受到共鸣激发方案的阻碍，这些方案被广泛用于获得高光子无法区分性。在这里，我们表明，声子辅助激发（一种保持不可区分性的方案）还允许完全利用极化的选择性光学转变来初始化并测量单个自旋状态。我们在低横向磁场中访问孔自旋系统的连贯性，并在激发态的辐射发射过程或量子点基态下直接监测自旋倾向。我们报告了旋转状态检测保真度为$ 94.7 \ pm 0.2 \％$ $ $ $ $ $ $ $ $ $ $ $ $ $ $ 20 \ pm5 $ 〜ns孔旋转相干时间，证明了该方案和系统的潜力，可以生成线性簇状态，并具有十几个光子
Spins in semiconductor quantum dots are promising local quantum memories to generate polarization-encoded photonic cluster states, as proposed in the pioneering Rudolph-Lindner scheme [1]. However, harnessing the polarization degree of freedom of the optical transitions is hindered by resonant excitation schemes that are widely used to obtain high photon indistinguishability. Here we show that acoustic phonon-assisted excitation, a scheme that preserves high indistinguishability, also allows to fully exploit the polarization selective optical transitions to initialise and measure single spin states. We access the coherence of hole spin systems in a low transverse magnetic field and directly monitor the spin Larmor precession both during the radiative emission process of an excited state or in the quantum dot ground state. We report a spin state detection fidelity of $94.7 \pm 0.2 \%$ granted by the optical selection rules and a $20\pm5$~ns hole spin coherence time, demonstrating the potential of this scheme and system to generate linear cluster states with a dozen of photons
