RUI: Coupling Trapped Ions to Bulk Piezoelectric Resonators

单个原子离子被隔离在真空金属室中，在那里它们可以被电力限制和悬浮，是新开发的用于通信、传感和计算的量子技术的关键组成部分。在大多数情况下，这些原子是由通过室内窗户的激光控制的，并通过探测原子发出的光来监测。当原子离子靠近固体表面时，它们可以表现出新的行为，从而可以消除对激光的需求，从而使量子控制完全以电子方式进行，这可以大大简化实验设置。PI和他的本科生将研究单个被捕获的原子离子与附近振动的压电晶体（piezo）的相互作用。这种类型的材料通常用于传感器，通过将它们直接转换为电信号来测量小的力或位移。如果能很好地理解离子-压电相互作用，则可以通过应用于附近捕获离子的量子传感技术来增强这种应用。研究小组将测量相互作用对几个参数的依赖性，包括离子与晶体之间的距离，以及悬浮捕获离子的振动频率，并将结果与理论模型进行比较。实验与理论的良好一致性将激励后续实验寻求用晶体控制离子，并最终设计和构建量子增强压电传感器。大部分实验，从设备设计和建造到数据采集和分析，将由本科生进行，帮助他们培养在量子信息科学与技术这一新兴领域进行研究生学习和职业所需的技能。PI将通过实验测量体压电谐振器耦合对捕获原子离子运动的影响。该实验将包括一个单电离的镱（Yb）原子，稳定地限制在射频（RF）离子阱中，放置在超高真空室内的锆钛酸铅压电谐振器（压电）附近。当压电陶瓷处于室温时，当与压电陶瓷的机械振动发生共振时，耦合应表现为离子运动的升温速率增加。通过对捕获离子进行温度测量，研究小组可以通过在真空平移台上移动压电片来推断这种耦合强度作为压电离子距离的函数。被捕获的原子Yb离子晶体已被证明是工程复杂量子系统的理想平台，其中离子之间的库仑排斥可以用来使用相干激光相互作用在晶体内产生纠缠。然而，当试图将离子数扩展到超过电流限制时，这种方法具有基本的局限性；一个可控的压电离子耦合可以帮助解决的问题。例如，可以将压电片放入光力学腔中，形成量子换能器，将离子运动的信息印入激光光束的频率调制中，使其可用于远距离传输。此外，压电材料被广泛用作机械传感器，并且将压电晶体和离子晶体耦合的能力可能导致用于压电读出的增强量子传感技术的发展。压电再次充当换能器，将机械振动转化为电子振动，而被捕获的离子对这种振动非常敏感。该项目由AMO实验物理项目和促进竞争性研究的既定项目（EPSCoR）共同资助。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。

Individual atomic ions, isolated in evacuated metal chambers where they can be confined and levitated by electric forces, are a key component of newly developing quantum technologies for communication, sensing, and computation. In most cases these atoms are controlled by laser light directed through the chamber’s windows and are monitored by detecting the light the atoms emit. When the atomic ions are brought close to solid surfaces, they can exhibit new behavior that could remove the need for the lasers, allowing quantum control to be performed entirely electronically, which could vastly simplify experimental setups. The PI and his undergraduate research students will study the interactions of a single trapped atomic ion with a nearby vibrating piezoelectric crystal (piezo). This type of material is commonly used in sensors to measure small forces or displacements by converting them directly into electrical signals. This application could be enhanced by quantum sensing techniques applied to a nearby trapped ion if the ion-piezo interactions were well understood. The research group will measure the dependence of the interaction on several parameters, including the distance between the ions and the crystal, and the vibrational frequency of the levitated trapped ion, and will compare the results to a theoretical model. Good agreement between experiment and theory will motivate follow-up experiments seeking to control the ions with the crystal and eventually to design and construct quantum enhanced piezo sensors. Much of the experiment, from apparatus design and building to data acquisition and analysis, will be performed by undergraduate students, helping them develop skills necessary for graduate studies and careers in the burgeoning field of quantum information science and technology. The PI will experimentally measure the effects of a bulk piezoelectric resonator coupling to the motion of trapped atomic ions. The experiment will consist of a singly ionized Ytterbium (Yb) atom, stably confined by a radiofrequency (RF) ion trap, placed in proximity to a bulk lead zirconate titanate piezoelectric resonator (piezo) within an ultra-high vacuum chamber. With the piezo at room temperature, the coupling should manifest itself as an increased heating rate of the ion’s motion when on resonance with the piezo's mechanical vibrations. By performing thermometry measurements on the trapped ion, the research team can infer the strength of this coupling as a function of piezo-ion distance by moving the piezo on an in-vacuum translation stage. Crystals of trapped atomic Yb ions have proven to be an ideal platform for engineering complex quantum systems, where the Coulomb repulsion between ions can be used to generate entanglement within a crystal using coherent laser interactions. However, this approach has fundamental limitations when attempting to scale the ion numbers past current limits; a problem which a controlled piezo-ion coupling could help solve. For instance, a piezo could be built into an optomechanical cavity to form a quantum transducer, imprinting information about the ion's motion into the frequency modulation of a laser beam and making it available for long-distance transmission. In addition, piezoelectric materials see wide use as mechanical sensors, and the ability to couple a piezo and ion crystal could lead to development of enhanced quantum sensing techniques for piezo readout. The piezo again serves as a transducer, transforming mechanical vibrations into electrical vibrations to which trapped ions are exquisitely sensitive. This project is jointly funded by the AMO Experimental Physics Program and the Established Program to Stimulate Competitive Research (EPSCoR).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.