QII-TAQS: A Chip-Scale Spin-Photon Memory Interface with Coherence Exceeding One Second

量子信息处理提供了一个由量子力学物理定律保护的安全牢不可破的网络。例如，量子密钥分发通过不可克隆定理和发送方与接收方之间的一次性密钥板提供了从根本上安全的光子通信通道，可以立即检测到通信通道中的窃听者。光量子网络的一般价值指标是安全密钥速率（每秒单光子量子比特）和信道物理距离（最高可达100公里）。各种量子密钥分发协议，如通过高维纠缠和芯片级光子集成，进一步提高了安全密钥速率。然而，提高量子比特物理传输距离需要为量子网络开发可扩展、长相干和高保真的量子存储器。此外，双节点配置的量子存储模块可以提供期待已久的量子中继器的科学里程碑-将量子网络距离扩展到大都市甚至大陆尺度。这个qi - taqs项目旨在开发基于超纯硅-28背景下深层供体硒-77的核自旋光子相互作用的芯片级硅量子比特存储器。该项目是由最近发现的77Se+的超精细核跃迁而实现的，该跃迁在光学上非常容易获得（以前认为有效质量理论是禁止的）。最近有报道称核自旋量子比特的相干时间长达1秒。利用微波调制可寻址的超精细自旋结构，甚至可以实现按需光子存储和动态改进存储。这一科学努力使量子网络走向实现，在基于硅的量子信息处理架构中得到支持。作为科学任务的补充，该项目有更广泛的教育工作，包括多样性推广、高中科学推广、研究生和本科生实践教学模块。该项目涉及与NIST和Argonne国家实验室的合作，为博士生的跨学科培训提供了肥沃的训练场地。该项目旨在在芯片可扩展的量子存储接口中，在超纯富集硅-28槽中推进深层供体77Se+，光微波同时控制和减相时间T2高达一秒。首先，研究小组寻求在光子晶体微腔中实现28Si:77Se+体系，显著提高核自旋-光子相互作用中的辐射效率和光子提取。该团队将研究珀塞尔增强辐射寿命的空腔，并寻求理解非辐射机制以及零光子线边界。其次，他们将通过光谱方法检查28Si:77Se+量子比特的相干寿命。这涉及自旋弛豫（T1）协议，非均匀相干时间（T2和T2*），以及量子比特的瞬时扩散。第三，他们提出在量子节点架构上实现28Si:77Se+超精细自旋光子接口作为量子存储器。这种可扩展的量子存储模块通过硅量子信息处理架构实现了光可访问的长核自旋相干的变革性平台。该项目由量子飞跃大创意计划和工程理事会的电气、通信和网络系统部门共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Quantum information processing provides a secure unbreakable network protected by the physical laws of quantum mechanics. Quantum key distribution, for example, provides fundamentally secure photon communication channels through the no-cloning theorem and the one-time key pad between the sender and receiver, wherein the eavesdropper in the communication channel can be immediately detected. The general figures-of-merit in an optical quantum network are the secure key rate (in single-photon qubits per second) and the channel physical distance (up to ~ 100 km as the record). Various protocols in quantum key distribution, such as through high-dimensional entanglement and chip-scale photonic integration, have further increased the secure key rate. Improving the qubit physical transmission distance, however, requires the development of a scalable, long-coherence, and high-fidelity quantum memory for the quantum network. Furthermore, a quantum memory module, in a two-node configuration, can provide the long-awaited scientific milestone of a quantum repeater -- scaling the quantum network distance to metropolitan and even continental scales. This QII-TAQS project aims to develop a chip-scale silicon qubit memory based on the nuclear spin-photon interactions of deep-donor selenium-77 in an ultrapure silicon-28 background. The project is enabled by recent discovery of a hyperfine nuclear transition of 77Se+ that is remarkably optically accessible (previously thought to be forbidden from effective mass theory). Long coherence time of the nuclear spin qubit up to a second has recently been reported. With the hyperfine spin structure addressable by microwave modulation, on-demand photon storage and dynamical improvement of the storage can even be possible. This scientific effort brings a quantum network towards realization, supported in a silicon-based architecture for quantum information processing. Complementing the scientific tasks, the project has a broader educational effort that includes diversity outreach, high-school science outreach, and hands-on graduate and undergraduate pedagogical modules. The project involves collaborative work with NIST and Argonne National Laboratory, providing a fertile training ground for the cross-disciplinary training of PhD students.This project aims to advance the deep-donor 77Se+ in an ultrapure enriched silicon-28 bath, with optical-microwave simultaneous control and dephasing times T2 up to a second, in a chip-scalable quantum memory interface. Firstly, the research team seeks to implement the 28Si:77Se+ system in a photonic crystal microcavity, significantly improving the radiative efficiency and photon extraction in the nuclear spin- photon interaction. The team will examine the cavity Purcell enhancement of radiative lifetimes, as well as seek to understand the non-radiative mechanisms along with the zero-photon line bounds. Secondly, they will examine the coherence lifetimes of the 28Si:77Se+ qubit through spectroscopic methods. This involves spin-relaxation (T1) protocols, the inhomogeneous coherence times (T2 and T2*), as well as qubit instantaneous diffusion. Thirdly, they propose to implement the 28Si:77Se+ hyperfine spin-photon interface as a quantum memory on the quantum node architecture. This scalable quantum memory module enables a transformative platform in optically-accessible long nuclear spin coherence, through a silicon quantum information processing architecture. This project is jointly funded by the Quantum Leap Big Idea Program and the Division of Electrical, Communication, and Cyber Systems in the Engineering Directorate.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.