Physics Department and Solid State Institute, Technion-Israel Institute of Technology, 32000 Haifa, Israel.
Physics Department and Solid State Institute, Technion-Israel Institute of Technology, 32000 Haifa, Israel. Department of Physics, University of Washington, Seattle, WA 98195, USA.
Science. 2016 Oct 28;354(6311):434-437. doi: 10.1126/science.aah4758. Epub 2016 Sep 8.
Photonic cluster states are a resource for quantum computation based solely on single-photon measurements. We use semiconductor quantum dots to deterministically generate long strings of polarization-entangled photons in a cluster state by periodic timed excitation of a precessing matter qubit. In each period, an entangled photon is added to the cluster state formed by the matter qubit and the previously emitted photons. In our prototype device, the qubit is the confined dark exciton, and it produces strings of hundreds of photons in which the entanglement persists over five sequential photons. The measured process map characterizing the device has a fidelity of 0.81 with that of an ideal device. Further feasible improvements of this device may reduce the resources needed for optical quantum information processing.
光子簇态是一种仅基于单光子测量的量子计算资源。我们使用半导体量子点通过周期性定时激发进动的物质量子位来确定性地产生长串偏振纠缠光子的簇态。在每个周期中，纠缠光子被添加到由物质量子位和之前发射的光子形成的簇态中。在我们的原型设备中，量子位是被限制的暗激子，它产生了数百个纠缠光子的串，其中纠缠在五个连续的光子中持续存在。所测量的特征化该设备的过程映射与理想设备的保真度为 0.81。该设备的进一步可行改进可能会减少光量子信息处理所需的资源。
