Microwave-to-optical quantum link

量子工程建立在上个世纪两个最有影响力的发展之上：信息技术和量子科学。原子物理学、纳米技术和材料科学的惊人进步使得人们可以用单个光子、电子或声子来控制原子的量子态、微观和介观自旋、电路和机械振荡器。今天的主要挑战是混合量子网络的设计和相干控制。用于处理量子信息的最先进的固态系统之一是基于与微波光子耦合和操纵的集成超导电路。虽然电路非常适合快速逻辑运算和状态合成，但光子是量子通信的唯一现实候选者，因为它们与环境的相互作用很弱，传输带宽很大，并且对热噪声有弹性。因此，微波和光学域之间的相干换能器将汇集最有前途的系统的优点。它代表了克服最先进量子工程系统局限性的基石技术。该项目的主要科学目标是开发第一个用于超导量子比特的光纤收发器。我们将使用它来产生和上变频弱微波信号到光域。该转换器将基于电信波长光子晶体腔和微波频率超导谐振器之间的参数增强电光机械耦合。虽然在概念上类似于声光调制器，但这种类型的转换器在绝对零度以上仅0.01度的温度下工作，其机械占据接近量子基态，并且它在每个谐振器寿命仅使用单个微波光子的情况下实现有效的光学调制。

Quantum engineering builds upon two of the most influential developments of the last century: information technology and quantum science. Spectacular advances in atomic physics, nanotechnology, and material science allow to control the quantum state of atoms, microscopic and mesoscopic spins, electrical circuits, and mechanical oscillators with individual photons, electrons or phonons. Today's major challenge is the design and coherent control of hybrid quantum networks. One of the most advanced solid-state systems for processing quantum information is based on integrated superconducting circuits coupled and manipulated with microwave photons. While electrical circuits are ideally suited for fast logical operations and state synthesis, optical photons are the only realistic candidates for quantum communication due to their weak interaction with the environment, large bandwidth of transmission, and resiliency to thermal noise. A coherent transducer between the microwave and the optical domains will therefore bring together the advantages of the most promising systems. It represents a cornerstone technology to overcome the limitations of state-of-the-art quantum engineered systems. The main scientific objective of this project is to develop the first fiber-optic transceiver for superconducting qubits. We will use it to generate and up-convert weak microwave signals to the optical domain. The converter will be based on the parametrically enhanced electro-optomechanical coupling between a telecom wavelength photonic crystal cavity and a microwave frequency superconducting resonator. While conceptually similar to an acousto-optic modulator, this type of converter is operated at a temperature of only 0.01 degrees above absolute zero, it's mechanical occupation is close to the quantum ground state and it achieves effective optical modulation with only a single microwave photon per resonator lifetime.