RAISE-TAQS: Inverting the design paradigm: Tunable qubits in hybrid photonic materials as a scalable platform for quantum photonic devices

固态电子学的出现通过小型、便携和功能强大的计算机的出现改变了人类社会。量子技术有望在信息传输、信息处理和传感方面带来同样革命性的变化。然而，在现有的几位器件演示和实现这些潜在增益所需的高度集成的多位器件之间存在巨大的差距。设计可扩展的、鲁棒的量子设备的新范例是实现这一领域潜力的关键。主要挑战之一是传统电子设备包含许多少数基本组件（例如晶体管）的实例。每个组件之间微小但不可避免的变化可以通过使用放大器和鉴别器等组件来克服。然而，像放大器这样的组件不能用于量子设备。因此，迄今为止，大多数简单的量子设备都围绕可用的特定量子比特的独特属性设计了整个设备。这种方法是不可扩展的。我们建议开发一种新的设计策略，允许在制造后和设备操作期间对各个量子位进行调整。我们相信这种方法不仅可以克服可扩展性的挑战，而且还可以实现一种新形式的量子并行处理，从而加快设备的运行速度。我们将开发允许调谐的材料和设备架构，同时保留对量子设备操作至关重要的量子位之间的强相互作用。我们还将开发新的算法，利用这种并行处理的机会。我们将通过一系列新课程和暑期研究项目为新兴的量子器件工程领域培养学生。技术我们建议反转量子器件的设计范式，创建一个平台，其中每个量子位都可以被调谐到与器件级设计波长共振。我们的原型量子位将是限制在InAs量子点分子（QDM）中的单个空穴自旋的取向：一对紧密间隔的QD，其中发射/吸收波长随施加的电场强烈调谐。从概念上讲，我们将开发的概念验证设备相当简单：包含多个量子位的光子晶体腔，这些量子位可以单独调谐到与腔模共振，以便可控地实现量子逻辑功能。为了实现这一概念，我们将开发可以在III-V外延结构中生长的金属/电介质超材料。我们将开发和采用逆向设计方法来创建光子腔，这些光子腔利用这些新的超材料来允许将电场应用于单个量子位，同时保持高腔质量（Q）和小腔模体积（V）。与此同时，我们将设计高保真度的门，这些门将朝着单次三量子位门构建，从而实现更快的计算和更低的电路深度。我们将通过以下方式为量子器件工程的新兴领域培养学生：1）本科生研究人员交换计划; 2）开发新的光子超材料本科生/格拉德课程;（3）两个星期的手-针对高中代表性不足的少数族裔的暑期项目。该奖项反映了NSF的法定使命，并且通过使用基金会的智力价值进行评估，被认为值得支持和更广泛的影响审查标准。

The advent of solid state electronics altered human society through the emergence of small, portable, and powerful computers. Quantum technologies promise an equally revolutionary change in information transmission, information processing, and sensing. However, there is an enormous gap between the existing demonstration of few-bit devices and the highly integrated multi-bit devices required to realize these potential gains. New paradigms for the design of scalable, robust quantum devices are the key to realizing the potential of this field. One of the major challenges is that traditional electronic devices contain many instances of a small number of fundamental components (e.g. transistors). The tiny, but inevitable, variation between each component can be overcome by using components such as amplifiers and discriminators. However, components like amplifiers cannot be used in quantum devices. As a result, most simple quantum devices to date have engineered the entire device around the unique properties of the particular quantum bits that are available. This approach is not scalable. We propose to develop a new design strategy that will allow the individual quantum bits to be tuned after fabrication and during device operation. We believe this approach will not only overcome the scalability challenges, but will also enable a new form of quantum parallel processing that will speed up device operation. We will develop the materials and device architectures that allow the tuning while preserving the strong interactions between the quantum bits that are crucial for quantum device operation. We will also develop new algorithms that take advantage of this parallel processing opportunity. We will train students for the emerging field of quantum device engineering through a series of new courses and summer research programs.TechnicalWe propose to invert the design paradigm for quantum devices, creating a platform in which each qubit can be tuned into resonance with a device-level design wavelength. Our prototype qubit will be the orientation of a single hole spin confined in an InAs Quantum Dot Molecule (QDM): a closely spaced pair of QDs in which the emission / absorption wavelength tunes strongly with applied electric field. Conceptually, the proof-of-concept device we will develop is fairly simple: a photonic crystal cavity containing multiple qubits that can be individually tuned into resonance with the cavity mode in order to controllably implement quantum logic functions. To realize this concept, we will develop metal / dielectric metamaterials that can be grown within III-V epitaxial structures. We will develop and employ inverse design methods to create photonic cavities that leverage these new metamaterials to allow application of electric fields to individual qubits while retaining high cavity quality (Q) and small cavity mode volume (V). In parallel, we will design high fidelity gates that build toward single-shot three-qubit gates that enable faster computation and lower circuit depth. We will train students for the emerging field of quantum device engineering through: 1) A cohort undergraduate researcher exchange program; 2) Development of a new undergrad / grad course on photonic metamaterials; and 3) A two-week hands-on summer program for high school underrepresented minorities.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.