CAREER: Controlling noise in quantum devices with light and sound

虽然对新生量子技术的掌握有望带来新形式的高性能计算、精确传感和无条件安全通信，但这些量子设备固有的噪声会降低其卓越特性的特性。对于各种各样的量子器件来说，最有问题的噪声源是由所谓的二能级隧穿态（TLS）产生的。虽然还没有得到很好的理解，但TLS无处不在-出现在晶体中，表面上和无序材料中-并且它们产生的噪音在许多量子技术操作所需的低温下更加尖锐。拟议的研究旨在利用TLS和声波之间的强烈相互作用来开发新技术，以控制和减少这种令人烦恼的噪声源。主要目标涉及工程设备：（1）通过设备几何形状塑造声音如何影响量子设备性能，以及（2）显示如何通过机械波的主动转导控制量子设备中的噪声。该项目探索了大幅降低TLS产生的噪声的能力，并揭示了目前未知的TLS微观起源，以实现量子技术的实际应用。通过付费的本科生研究机会，关于光物质相互作用的新课程，和量子科学为主题的拓展-侧重于历史上少数民族的社区-拟议的教育目标旨在解决系统性的妇女和少数群体在物理科学和增加获得职业生涯在亚利桑那州的新兴技术部门代表性不足的群体。该项目旨在展示控制噪音产生的两个-水平隧穿态（TLS）通过操纵声子自由度，并显示如何控制可以用来提高量子器件的性能。为了实现这些目标，电子，声子和光子器件将被创建：（1）从高度限制的膜，波导和谐振器，改变和控制声子态密度，预计将大幅改变和重塑TLS噪声的频谱，以及（2）其中光可以被利用来抑制大振幅机械波，预计通过“饱和”TLS损耗来降低噪声。脉冲序列测量、微波光谱学和一种新形式的泵浦-探测声子光谱学将把器件性能与声子操纵联系起来。然而，详细的理论-实验比较将阐明声子限制和转导对TLS产生的各种噪声和耗散机制的影响，例如，以机械品质因数的温度依赖性的形式。 该项目将展示（1）如何在高度受限的结构阵列中改变TLS噪声，（2）如何使用声子来控制微波域中的TLS噪声，以及（3）如何利用声子首次提高量子器件性能。总之，这些结果预计将确定声子操纵可以延长超导量子比特内电磁量子态的寿命，并可能为量子计算的实用形式和力，旋转，该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响进行评估，被认为值得支持审查标准。

While the mastery of nascent quantum technologies promises new forms of high-performance computing, precision sensing, and unconditionally secure communications, noise inherent to these quantum devices degrades the very features that enable their remarkable properties. The most problematic source of noise for a wide variety of quantum devices is produced by so-called two-level tunneling states (TLSs). While not well understood, TLSs are ubiquitous—appearing in crystals, on surfaces, and within disordered materials—and the noise they produce is more acute at the low temperatures required for the operation of many quantum technologies. The proposed research aims to leverage the strong interaction between TLSs and sound waves to develop new techniques to control and reduce this vexing source of noise. Key objectives involve engineering devices: (1) to shape how sound impacts quantum device performance through device geometry, and (2) to show how noise in quantum devices can be controlled through the active transduction of mechanical waves. This project explores the ability to drastically reduce the noise produced by TLS and shed light on the—currently unknown—microscopic origin of TLSs, toward practical applications of quantum technology. Through paid undergraduate research opportunities, new curricula on light-matter interactions, and quantum science themed outreach—focusing on historically minoritized communities—the proposed educational objectives aim to address systemic underrepresentation of women and minority groups in the physical sciences and increase accessibility to careers in Arizona’s burgeoning technology sector to underrepresented groups.This project aims to demonstrate control of noise produced by two-level tunneling states (TLSs) through the manipulation of phononic degrees of freedom and to show how this control can be used to improve the performance of quantum devices. To achieve these objectives, electronic, phononic and photonic devices will be created: (1) from highly confined membranes, waveguides and resonators that alter and control the phonon density of states, predicted to drastically alter and reshape the spectrum of TLS noise, and (2) where light can be harnessed to transduce large amplitude mechanical waves, expected to reduce noise by “saturating” TLS losses. Pulse sequence measurements, microwave spectroscopy and a new form of pump-probe phonon spectroscopy will connect device performance with phonon manipulation. Whereas, detailed theory-experiment comparison will elucidate the impact of phonon confinement and transduction on various noise and dissipation mechanisms produced by TLS, e.g., in the form of the temperature dependence of the mechanical quality factor. This project will show (1) how TLS noise can be altered in an array of highly confined structures, (2) how phonons can be used to control TLS noise in the microwave domain, and (3) how phonons can be leveraged to improve quantum device performance for the first time. Together, these results are expected to establish that phonon manipulation can extend lifetimes of electromagnetic quantum states within superconducting qubits and may pave the way for practical forms of quantum computing and ultra-sensitive detectors of forces, rotation, magnetic fields and displacement.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.