Council for Scientific and Industrial Research (CSIR) National Laser Centre, PO Box 395, Pretoria 0001, South Africa.
Council for Scientific and Industrial Research (CSIR) National Laser Centre, PO Box 395, Pretoria 0001, South Africa.; School of Physics, University of Witwatersrand, Johannesburg 2000, South Africa.
Sci Adv. 2016 Feb 26;2(2):e1501165. doi: 10.1126/sciadv.1501165. eCollection 2016 Feb.
Many protocols in quantum science, for example, linear optical quantum computing, require access to large-scale entangled quantum states. Such systems can be realized through many-particle qubits, but this approach often suffers from scalability problems. An alternative strategy is to consider a lesser number of particles that exist in high-dimensional states. The spatial modes of light are one such candidate that provides access to high-dimensional quantum states, and thus they increase the storage and processing potential of quantum information systems. We demonstrate the controlled engineering of two-photon high-dimensional states entangled in their orbital angular momentum through Hong-Ou-Mandel interference. We prepare a large range of high-dimensional entangled states and implement precise quantum state filtering. We characterize the full quantum state before and after the filter, and are thus able to determine that only the antisymmetric component of the initial state remains. This work paves the way for high-dimensional processing and communication of multiphoton quantum states, for example, in teleportation beyond qubits.
许多量子科学协议，例如线性光学量子计算，都需要访问大规模纠缠量子态。这种系统可以通过多粒子量子位来实现，但这种方法往往存在可扩展性问题。另一种策略是考虑存在于高维态中的较少粒子。光的空间模式就是这样一种候选者，它提供了对高维量子态的访问，从而增加了量子信息系统的存储和处理能力。我们通过 Hong-Ou-Mandel 干涉演示了对轨道角动量纠缠的双光子高维态的受控工程。我们制备了大范围的高维纠缠态，并实现了精确的量子态滤波。我们在滤波器前后对全量子态进行了表征，从而能够确定只有初始态的反对称分量保留下来。这项工作为多光子量子态的高维处理和通信铺平了道路，例如，在超越量子比特的量子隐形传态中。
