QC:SCALE - Quantum Circuits: Systematically Controlling And Linking Emitters for integrated solid state photonics platforms

该项目研究了一种很有前途的固态体系结构，可以扩展到构建量子信息处理器。我们专注于一个众所周知的系统，钻石中的NV缺陷中心。该中心具有与光子良好耦合的基态自旋，从而可以设想通过低损耗波导耦合的自旋阵列。然而，与原子系统相比，固态带来了更大的消相干和光谱非均匀性。它还带来了利用纳米制造在规模上建立自旋和光子界面的前景。在这里，我们的目标是单独寻址固态发射体，控制它们的自旋，并使它们在光谱上无法区分，从而确保通过芯片上的波导连接的高保真自旋量子比特。虽然固态量子光子学领域的大部分注意力都集中在寻找一种表现出原子性质的理想固态发射体上，但在弄清楚如何围绕它们建立复杂的光电子系统以实现精确的光学和自旋控制方面，人们花费的努力相对较少。这一点尤其重要，因为传统的自上而下的半导体制造方法不能直接应用于这种自下而上的系统。由于一台完全纠错的量子计算机将需要O(1E6)个量子比特，即使是近期有噪声的中等尺度量子(NISQ)设备也需要O(1E2)来证明计算量子优势，因此迫切需要建立使用固态发射器的自下而上系统可以被放大以与自上而下制造的系统(例如用于线性光学和超导电路的系统)竞争。NV-Center提供了一个具有光学和自旋自由度的室温量子系统，可以访问和操纵，这种室温读数使NV-Center对于电气和光学领域的设备的快速迭代和原型都很有吸引力。此外，纳米钻石形式的高相干NV中心的现成供应使我们能够直接实施最初在生物化学领域开发的自下而上的制造方法，例如精密定位和固态量子光学的模板化自组装。

This project investigates a promising solid state architecture that could be extended to build a quantum information processor. We focus on a well understood system, the NV-defect centre in diamond. This centre has a ground state spin that is well coupled to photons such that arrays of spins coupled by low loss waveguides can be envisaged. However the solid state brings increased decoherence and spectral non-uniformity compared to atomic systems. It also brings the prospect of building spin and photonic interfaces at scale, using nanofabrication. Here we aim to individually address solid-state emitters control their spin and make them spectrally indistinguishable thus ensuring high fidelity spin quantum bits linked by waveguides on a chip. While most of the focus of the solid-state quantum photonics community has been devoted to finding an ideal solid-state emitter that exhibits atom-like properties, relatively little effort has been spent on figuring out how one can build complex opto-electronic systems around them enabling precise optical and spin control. This is especially important, given that traditional top-down semiconductor manufacturing methods cannot be directly applied to such bottom-up systems. Since a fully error corrected quantum computer will need O(1E6) qubits and even near-term noisy intermediate scale quantum (NISQ) devices need O(1E2) to demonstrate computational quantum supremacy, there is an urgent need to establish that bottom up systems employing solid state emitters can be scaled up to be competitive with top-down fabricated systems (such as those employed for linear optics and superconducting circuits). The NV- centre provides a room-temperature quantum system with optical and spin degrees of freedom that can be accessed and manipulated and this room temperature readout makes the NV- centre attractive for rapid iteration and prototyping of devices, both in the electrical and optical domain. In addition, the ready availability of high coherence NV- centres in nanodiamond form allows us to directly implement bottom-up manufacturing methods, originally developed in the bio-chemistry domain, such as precision localisation and templated self-assembly to solid state quantum optics.