Photogenerated Multi-Spin Systems as Qubits for Quantum Information Science

西北大学化学系的Michael Wasielewski教授正在研究如何通过有机分子控制电荷和自旋输运，这对未来量子信息科学在计算、传感和通信方面的应用至关重要。该项目由化学系化学结构、动力学和机制B项目资助。化学对分子结构和性质的控制程度使得开发利用电子自旋动力学来实现量子信息科学新策略的分子和材料成为可能。分子结构为使用自下而上的合成策略定制量子特性提供了无与伦比的灵活性。该项目处于有机、物理和材料化学的交叉点，因此非常适合各级科学家的教育。这个群体也处于有利地位，可以为科学领域代表性不足的学生提供最高水平的教育和培训。涉及K-12学生的外展活动也将是资助项目的一部分。该项目将解决利用自旋相关基对（SCRPs）作为针对量子信息科学应用的自旋量子比特对（SQPs）所必需的几个目标。Michael Wasielewski教授的团队将1)光生成SCRPs以产生定义良好的初始SQP量子态，这些量子态可以被寻址和操纵，作为双量子位量子门的目标；2)将量子粒子的电子自旋与一个或两个核自旋纠缠，延长自旋相干寿命；3)在两个站点之间移动（传送）自旋相干，重点研究SQP相干寿命和增加传送距离对传送保真度的影响；4)探索手性诱导的自旋选择性如何影响手性电子供体-受体分子的SQP相干性和极化。在主题1、3和4中，他们将扩展分子架构，包括DNA发夹，这将为各种分子量子信息科学系统的快速合成提供可扩展的平台。这些系统的自旋动力学将使用时间分辨电子顺磁共振实验来探测，该实验将使用短激光脉冲来产生SCRP，然后使用恒定或脉冲微波探测自旋。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。

In this project, funded by the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Professor Michael Wasielewski of the Department of Chemistry at Northwestern University is developing a fundamental understanding of how to control charge and spin transport through organic molecules that is critical to the future of quantum information science applications for computation, sensing, and communications. The degree of control over molecular structure and properties afforded by chemistry makes it possible to develop molecules and materials that take advantage of electron spin dynamics to implement new strategies for quantum information science. Molecular architectures provide unmatched flexibility for tailoring quantum properties using bottom-up synthetic strategies. The project lies at the interface of organic, physical, and materials chemistry, and is therefore well suited to the education of scientists at all levels. This group is also well-positioned to provide the highest level of education and training for students underrepresented in science. Outreach activities involving K-12 students will also be part of the funded project.This project will address several goals essential for exploiting spin-correlated radical pairs (SCRPs) as spin qubit pairs (SQPs) that target quantum information science applications. Professor Michael Wasielewski’s group will 1) photogenerate SCRPs to produce well-defined initial SQP quantum states that can be addressed and manipulated to serve as targets for two-qubit quantum gates; 2) entangle the electron spins of SQPs with one or two nuclear spins to extend spin coherence lifetimes; 3) move (teleport) spin coherences between two sites, focusing on how SQP coherence lifetimes and increasing the teleportation distance affect teleportation fidelity; and 4) explore how chirality-induced spin selectivity influences SQP coherence and polarization using chiral electron donor-acceptor molecules. In topics 1, 3, and 4, they will extend the molecular architectures to include DNA hairpins, which will provide a scalable platform for the rapid synthesis of a wide variety of molecular quantum information science systems. The spin dynamics of these systems will be probed using time-resolved electron paramagnetic resonance experiments, which will be performed using a short laser pulse to generate the SCRP following by probing the spins using constant or pulsed microwaves.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.