A Hybrid Photonics Device for Efficient Quantum Entanglement

非技术摘要利用量子力学的量子计算机将能够解决在当今类型的计算机上不容易处理的问题。一个与国家安全相关的例子是将大数分解为分量素数。这项计算困难的任务是用于安全通信的现代加密协议的基础。与材料发现相关的一个例子是量子模拟。由于材料内部原子之间的相互作用是量子力学的，因此一个高效的材料模拟器也必须具有量子力学的特征。量子计算机的一个关键资源是量子纠缠。在这个项目中，我们将设计、实现和测试钻石中的集成量子电路，目的是显著提高量子纠缠的生成率。具体地说，我们的目标是通过整合三个专门的层来提高这一速度：基于钻石中发光缺陷的量子层，将光子传送到钻石芯片表面的光子层，以及检测单个光子的探测器层。这些片上集成的光子电路将成为未来量子计算机的处理器芯片或量子网络的一个节点。更快的纠缠率将影响我们扩大用于计算的量子比特数量的能力。作为这项研究的一个可整合的部分，研究生和本科生将接受纳米制造、集成光子学和量子技术方面的培训，这些领域目前在工业和政府实验室中需求很高。技术摘要量子纠缠是量子信息处理的基本资源，理论上可以通过光子测量有效地进行预测。被宣布的计划有一些显著的特点。首先，量子比特不需要移动。其次，量子比特不需要相互作用。后一种情况限制了可能存在的消相干通道的数量，从而提高了可伸缩性的前景。最后，光子介导的纠缠是唯一适合(也许只能通过)片上集成光子学实现的。该方案旨在实现一种片上集成的光子纠缠发生器。集成的光子纠缠发生器基于不同材料的分层器件，以实现集成功能：(1)钻石中的量子缺陷，(2)磷化镓光子层，以及(3)波导集成的NbN超导单个探测器。集成的主要目标是提高纠缠生成率，使之能够扩展到大型(2)量子比特网络。忽略集成器件中的光子纯度的估计表明千赫兹频率是可能的，比自由空间实施方案大五个数量级。然而，我们强调，在集成量子光子学的当前状态下，在可扩展的平台上简单地超越自由空间实现将是一项重大成就。将进行设备和系统级别的评估，以提供高效系统的路线图。基于测量的纠缠的高效产生的展示有望推动集成光子学作为通用量子计算平台的可行性。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Non-Technical AbstractQuantum computers, which utilize quantum mechanics, will be able to solve problems that are not tractable on today's types of computers. An example relevant to national security is the factorization of large numbers into component prime numbers. This computationally hard task underlies modern encryption protocols used for secure communication. An example relevant to materials discovery is quantum simulation. Because interactions between atoms within a material are quantum mechanical, an efficient materials simulator must also have quantum mechanical features. A critical resource for quantum computers is quantum entanglement. In this project, we will design, implement, and test integrated quantum circuits in diamond with the aim to significantly increase quantum entanglement generation rates. Specifically, we aim to increase this rate by integrating three specialized layers: a quantum layer based on light-emitting defects in diamond, a photonic layer which routes photons on the surface of the diamond chip, and a detector layer which detects the single photons. These on-chip integrated photonic circuits would then be the processor chip for a future quantum computer or a node of a quantum network. Faster entanglement rates will impact our ability to scale up the number of quantum bits used for calculations. As an integrable part of this research, graduate students and undergraduate students will be trained in nanofabrication, integrated photonics, and quantum technologies, skill areas currently in high demand in industry and government labs.Technical AbstractQuantum entanglement, a fundamental resource for quantum information processing, can theoretically be efficiently heralded via photon measurement. Heralded schemes have some striking characteristics. First, qubits do not need to be moved. Second, qubits do not need to interact with each other. This latter condition limits the number of decoherence channels that may be present, boosting the prospects for scalability. Finally, photon-mediated heralded entanglement is uniquely suited to (and perhaps can only be realized by) on-chip integrated photonics. This proposal seeks to realize an on-chip integrated photonics entanglement generator. The integrated photonics entanglement generator is based on a layered device of different materials for integrated functionality: (1) quantum defects in diamond, (2) a gallium phosphide photonics layer, and (3) waveguide-integrated NbN superconducting single detectors. The main goal of integration is to increase the entanglement generation rate to enable scaling to large (2) qubit networks. Estimates that neglect the photon purity in the integrated device indicate kHz rates are possible, five orders of magnitude greater than free space implementations. However, we emphasize that at the current state of integrated quantum photonics, it will be a major achievement to simply outperform free space implementations in a scalable platform. Device and system-level evaluation will be performed to give a roadmap toward efficient systems. The demonstration of efficient generation of measurement-based entanglement is expected to propel integrated photonics into viability as a universal quantum computation platform.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.