Mechanically-Mediated Spin Entanglement in Diamond

量子力学的基本方面，如量子态的叠加和纠缠，原则上可以用来解决传统经典计算机无法解决的计算问题。然而，实现这一目标在技术上仍然具有挑战性，因为这些量子特性对噪声和与环境的相互作用非常敏感，因此需要精确控制存储量子信息的单个量子位之间的相互作用。该项目将尝试在纳米机械谐振器中使用声波来调解固态系统中两个量子比特之间的相互作用。声波的传播速度比光慢得多，它们不能在真空中传播。因此，声波可以方便地被限制和引导在固体中。通过这种方式，这些机械波通过实现量子位之间的片上通信，提供了优于基于光子学的平台的优势。该计划的近期目标是通过机械介导的相互作用在两个量子比特之间产生量子纠缠。长期目标是开发一个基于力学的平台，用于实现固态量子计算机。该项目将促进教育和人力资源，为研究生和本科生提供科学和技术重要领域的优秀培训。该项目旨在演示自旋-力学系统中的力学介导自旋纠缠，建立基于力学的量子计算固态平台。 研究工作将使用金刚石纳米机械谐振器进行，其中两个电子自旋耦合到一个共同的机械模式。 该实验平台利用氮空位（NV）中心的强激发态应变耦合进行自旋-机械耦合，但通过光学控制的基态自旋的绝热演化来避免激发态的退相干。 将研究单个NV中心和单个声子之间的相干耦合。 随后将通过单声子交换研究两个NV中心之间的相干耦合。这些努力的成功实施应该能够实现两个NV中心之间的机械介导纠缠的追求。 Sorensen-Molmer纠缠方案，这是相对强大的热机械运动，将用于产生最大纠缠自旋态。

Fundamental aspects of quantum mechanics, such as the superposition and entanglement of quantum states, can, in principle, be exploited to solve computational problems that are impractical or impossible to solve with conventional, classical computers. Realizing this goal remains technically challenging, however, because these quantum traits are delicate and sensitive to noise and interactions with the environment, therefore requiring precise control of the interactions between the individual qubits which store quantum information. This project will attempt to use acoustic waves in a nano-mechanical resonator to mediate interactions between two qubits in a solid-state system. Acoustic waves propagate much more slowly than light, and they cannot propagate in a vacuum. As a result, acoustic waves can be conveniently confined and guided in a solid. In this way, these mechanical waves offer advantages over photonics-based platforms by enabling on-chip communication between qubits. The near-term goal of this program is to generate quantum entanglement between two qubits via mechanically-mediated interactions. The long-term goal is to develop a mechanics-based platform for implementation of a solid-state quantum computer. This project will promote education and human resources by providing excellent training to graduate and undergraduate students in areas of both scientific and technological importance. This project aims to demonstrate mechanically-mediated spin entanglement in a spin-mechanical system, establishing a mechanics-based solid-state platform for quantum computing. The research efforts will be carried out with a diamond nanomechanical resonator in which two electron spins couple to a common mechanical mode. This experimental platform exploits the strong excited-state strain coupling of nitrogen vacancy (NV) centers for spin-mechanical coupling, but circumvents decoherence of the excited states through optically-controlled adiabatic evolution of the ground spin states. Coherent coupling between a single NV center and a single phonon will be investigated. This will be followed by the study of coherent coupling between two NV centers through the exchange of single phonons. The successful implementation of these efforts should then enable the pursuit of mechanically-mediated entanglement between two NV centers. The Sorensen-Molmer entanglement scheme, which is relatively robust against thermal mechanical motion, will be used for the generation of a maximally-entangled spin state.