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

固态电子产品的出现改变了人类社会，出现了小型、便携式和功能强大的计算机。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，现有的几位设备演示与实现这些潜在收益所需的高度集成的多位设备之间存在着巨大的差距。设计可扩展的、健壮的量子设备的新范例是实现该领域潜力的关键。主要挑战之一是，传统电子设备包含少量基本组件(例如晶体管)的许多实例。每个组件之间微小但不可避免的差异可以通过使用放大器和鉴别器等组件来克服。然而，像放大器这样的部件不能用于量子设备。因此，到目前为止，大多数简单的量子设备都是围绕可用的特定量子比特的独特属性来设计整个设备。这种方法是不可扩展的。我们建议开发一种新的设计策略，允许在制造后和器件运行期间对单个量子比特进行调谐。我们相信，这种方法不仅将克服可伸缩性挑战，还将实现一种新形式的量子并行处理，将加快设备操作。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比特之间的强烈相互作用。我们还将开发利用这一并行处理机会的新算法。我们将通过一系列新的课程和暑期研究计划，为新兴的量子设备工程领域培养学生。技术我们建议颠覆量子设备的设计范式，创建一个平台，在其中每个量子比特都可以与设备级设计波长共振。我们的原型量子比特将是限制在InAs量子点分子(QDM)中的单个空穴自旋的取向：一对紧密间隔的量子点，其中发射/吸收波长与外加电场强烈调谐。从概念上讲，我们将开发的概念验证设备相当简单：一个包含多个量子比特的光子晶体腔，这些量子比特可以单独调谐到与腔模式的共振，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/介电超材料。我们将开发和使用反向设计方法来创建光子腔，这些方法利用这些新的超材料来允许向单个量子比特施加电场，同时保持高腔质量(Q)和小腔模体积(V)。与此同时，我们将设计高保真的门，使之朝着单激发三量子位门的方向发展，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新兴的量子设备工程领域培训学生：1)本科生研究人员交流计划；2)开发新的本科生/研究生光子超材料课程；3)为未被充分代表的少数族裔的高中学生提供为期两周的实践暑期计划。该奖项反映了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。

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.