Spiraling Into Control: Ultra High-Impedance Superconducting Resonators for Strongly-Coupled Spin-Cavity QED

量子技术有可能为计算、通信和传感提供资源高效的方法。量子信息处理的两个主要平台是半导体和超导电路中的电子自旋量子比特。这项研究旨在将这两个系统耦合在一起，创建一个由腔中单电子自旋组成的混合量子系统，这可能在计量学和量子计算等领域有不同的应用。此外，该项目旨在通过让罗切斯特市学区的高中暑期实习生参与拟议的研究并与高中教师一起开发量子科学课程材料，扩大未被充分代表的少数族裔的参与，改善STEM教育。本文提出的研究将探索单个电子自旋量子比特与超导微波光子之间的量子力学相互作用的新方法，目标是在自旋腔QED系统中建立强耦合。尽管之前已经证明了自旋和超导微波谐振器之间的耦合，但这种相互作用还不够强，不足以用于强大的量子信息处理应用，包括自旋光子状态转换和远距离自旋量子比特之间的多量子比特操作。为了克服这一挑战，拟议的研究将探索一种新型的螺旋微波谐振器，由于其高阻抗，预计它将比以前的谐振器具有更强的自旋-光子耦合强度。这一提议旨在通过制造Nb螺旋谐振器并将其与量子点自旋量子比特设备集成来验证这一预测。这项工作实现了大的自旋-光子耦合，将为实现自旋之间的远程相互作用、自旋-光子态转换以及创建新的混合量子系统铺平道路。这一奖项反映了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。

Quantum technology has the potential to provide resource-efficient approaches to computing, communication, and sensing. Two leading platforms for quantum information processing are electron-spin qubits in semiconductors and superconducting circuits. This study aims to couple these two systems together to create a hybrid quantum system consisting of a single electron spin in a cavity which may have diverse applications in fields like metrology and quantum computing. Furthermore, this project aims to broaden participation of underrepresented minorities and improve STEM education by involving high-school summer interns from the Rochester City School District in the proposed research and developing course material on quantum science together with high-school teachers.The research proposed here will explore a new approach for quantum-mechanical interaction between individual electron-spin qubits and superconducting microwave photons, with the goal to establish strong coupling in a spin-cavity QED system. Although coupling between spins and superconducting microwave resonators has previously been demonstrated, the interaction is not strong enough for robust quantum-information-processing applications, including spin-photon state transduction and multi-qubit operations between distant spin qubits. To overcome this challenge, the proposed research will explore a new type of spiral microwave resonator, which is predicted to enable much stronger spin-photon coupling strengths than previous resonators, owing to its high impedance. This proposal aims to verify this prediction by fabricating niobium spiral resonators and integrating them with quantum dot spin-qubit devices. The large spin-photon coupling enabled by this work will pave the way for the realization of long-distance interactions between spins, spin-photon state transduction, and the creation of new hybrid quantum systems.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.