The angular momentum of molecules, or, equivalently, their rotation in three-dimensional space, is ideally suited for quantum control. Molecular angular momentum is naturally quantized, time evolution is governed by a well-known Hamiltonian with only a few accurately known parameters, and transitions between rotational levels can be driven by external fields from various parts of the electromagnetic spectrum. Control over the rotational motion can be exerted in one-, two-, and many-body scenarios, thereby allowing one to probe Anderson localization, target stereoselectivity of bimolecular reactions, or encode quantum information to name just a few examples. The corresponding approaches to quantum control are pursued within separate, and typically disjoint, subfields of physics, including ultrafast science, cold collisions, ultracold gases, quantum information science, and condensed-matter physics. It is the purpose of this review to present the various control phenomena, which all rely on the same underlying physics, within a unified framework. To this end, recall the Hamiltonian for free rotations, assuming the rigid rotor approximation to be valid, and summarize the different ways for a rotor to interact with external electromagnetic fields. These interactions can be exploited for control—from achieving alignment, orientation, or laser cooling in a one-body framework, steering bimolecular collisions, or realizing a quantum computer or quantum simulator in the many-body setting.

中文翻译：

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分子旋转的量子控制

分子的角动量，或等效地，它们在三维空间中的旋转，非常适合于量子控制。分子角动量可以自然地量化，时间演化由众所周知的哈密顿量控制，哈密顿量仅具有几个准确已知的参数，并且旋转能级之间的过渡可以由电磁频谱各个部分的外部场驱动。对旋转运动的控制可以在一个，两个和多个主体的场景中进行，从而允许人们探测安德森定位，双分子反应的目标立体选择性或对量子信息进行编码，仅举几个例子。量子控制的相应方法是在单独的（通常是不相交的）物理学子领域中寻求的，包括超快科学，冷碰撞，超冷气体，量子信息科学和凝聚态物理。这篇综述的目的是在一个统一的框架内展示各种控制现象，它们都依赖于相同的基础物理。为此，假设刚性转子近似有效，请回忆哈密顿自由旋转，并总结转子与外部电磁场相互作用的不同方式。可以利用这些相互作用进行控制-从在一个人体框架中实现对准，定向或激光冷却，控制双分子碰撞，或在​​多体环境中实现量子计算机或量子模拟器来进行控制。为此，假设刚性转子近似有效，请回忆哈密顿自由旋转，并总结转子与外部电磁场相互作用的不同方式。可以利用这些相互作用进行控制-从在一个人体框架中实现对准，定向或激光冷却，控制双分子碰撞，或在​​多体环境中实现量子计算机或量子模拟器来进行控制。为此，假设刚性转子近似有效，请回忆哈密顿自由旋转，并总结转子与外部电磁场相互作用的不同方式。可以利用这些相互作用进行控制-从在一个人体框架中实现对准，定向或激光冷却，控制双分子碰撞，或在​​多体环境中实现量子计算机或量子模拟器来进行控制。