Ultrahigh-vacuum cryostat für hybrid quantum experiments with ultracold Rydberg atoms

提出了一种用于实现和研究由超冷里德伯原子组成的量子杂化系统与固态机电系统耦合的装置。该装置将用于研究量子力学中的基本问题，如退相干和经典物理与量子物理之间的跃迁。同时，在基于微波的固态量子计算机和单光子编码的“飞行”量子比特之间操纵和传输量子信息的新方法将被研究和开发。整个装置由一个超高真空低温恒温器组成，其中一方面可以产生和处理磁性和光学捕获的超冷原子，另一方面可以操作机电谐振器和超导电路。整个装置的其他组件包括用于光学冷却和捕获以及铷原子的里德伯激发的激光器，微波信号发生器，用于GHz频率范围内机电系统的激励和读出的网络分析仪，以及用于测量光子之间的光子相关性和纠缠的8通道单光子探测器光学光子和单微波光子或声子在固态系统中。所提出的组件将与在室温真空室中研究里德伯激励的前身装置相结合。计划在低温环境下进行的实验是探索Rydberg-Rydberg相互作用和Rydberg阻断机制的一种全新方法。我们的团队已经成功地利用这种机制在单光子水平上产生光学非线性，并在单光子之间产生有效的相互作用。这允许实现量子光开关元件，如晶体管和单光子逻辑门，它们是量子信息设置的核心组件。在这个新装置中，我们正在推进的方法将应用于一个全新的量子系统，微机械振荡器（MEMS）。例如，光学非线性将用于产生和读出MEMS的非经典振荡状态。除了关于“大”物体量子力学的基本问题外，量子态的MEMS作为超导量子计算机的量子传感器和量子信息存储设备也引起了人们的极大兴趣。特别是，我们的研究项目旨在实现微波量子计算机的光接口，使这些机器能够远距离联网。

An apparatus for the realization and investigation of quantum hybrid systems consisting of ultracold Rydberg atoms coupled to solid-state electromechanical systems is proposed. The apparatus will be used to investigate fundamental issues in quantum mechanics such as decoherence and transition between classical and quantum physics. At the same time, novel methods for manipulating and transferring quantum information between microwave-based solid-state quantum computers and "flying" qubits encoded in single optical photons will be investigated and developed. The overall apparatus consists centrally of an ultra-high vacuum cryostat in which, on the one hand, magnetically and optically trapped ultracold atoms can be generated and processed and, on the other hand, electromechanical resonators and superconducting circuits can be operated. Other components of the overall apparatus include lasers for optical cooling and trapping and for Rydberg excitation of rubidium atoms, a microwave signal generator, a network analyzer for excitation and readout of the electromechanical systems in the GHz frequency range, and an 8-channel single photon detector for measuring photon-photon correlations and entanglement between optical photons and single microwave photons or phonons in the solid-state system. The proposed components will be combined with a predecessor setup in which Rydberg excitations were studied in a room temperature vacuum chamber. The planned experiments in a cryogenic environment are a fundamentally new approach to exploiting Rydberg-Rydberg interactions and the Rydberg blockade mechanism. Our group has been successfully using this mechanism for several years to generate optical nonlinearities at the single photon level and resulting effective interactions between single photons. This allows the realization of quantum optical switching elements such as transistors and single photon logic gates, which are a central component of quantum information setups. In this new apparatus, the approach we are advancing will be applied to an entirely new quantum system, a micro-mechanical oscillator (MEMS). For example, optical nonlinearity will be used to generate and read out non-classical oscillatory states of the MEMS. In addition to fundamental questions about the quantum mechanics of "large" objects, MEMS in the quantum regime are of great interest as quantum sensors and quantum information storage devices for superconducting quantum computers. In particular, our research project aims at the realization of an optical interface for microwave quantum computers, which enables the networking of these machines over long distances.