Controlled Immersion of Single Neutral Atomic Impurities into an Ultracold Quantum Gas of a Different Atomic Species

对量子系统进行单粒子分辨率的相干控制，使人们有可能在基本水平上揭示量子力学现象，并将其用于设计任意量子态。在这个项目中，这种控制是通过控制一个原子物种的单个或几个中性原子浸入另一个原子物种的量子气体中来实现的。该项目将设计工具，通过物种选择性光学陷阱独立定位和控制两个子系统；通过标准吸收和荧光成像独立读出；以及通过物种间Feshbach共振调节和切换相互作用强度。该系统将探索两个主要场景：首先，该项目将解决在量子气体中冷却单个量子比特是否可能同时保持其内部状态相干性的问题，这与量子信息目的高度相关。其次，对于强烈的物种间相互作用，系统可以用准粒子方法很好地描述，其中来自量子气体的原子包围着杂质。这种极化子类似于通常固态物理中被声子覆盖的电子，具有通常固态系统中找不到的显著性质。该项目将在单个和多个杂质原子的交叉中创建和研究极化子，并研究它们的性质，如它们的自局域化。

Coherent control of quantum systems with single-particle resolution opens the possibility to shed light on quantum mechanical phenomena on a fundamental level and exploit them for engineering arbitrary quantum states. In this project, such a control is envisioned by controlled immersion of single or few neutral atoms of one atomic species in a quantum gas of another species. The project will devise tools for independent positioning and controlling the two sub-systems by species-selective optical traps; for independent read-out by standard absorption and fluorescence imaging; and for tuning and switching the interaction strength by inter-species Feshbach resonances. Two major scenarios will be explored with this system: First the project will address the question if cooling of single qubits in a quantum gas is possible while preserving their internal state coherences, highly relevant for quantum information purposes. Second, for strong inter-species interaction, the system is well described by a quasi-particle approach, where atoms from the quantum gas surround the impurities. Such polarons, analogous to electrons dressed by phonons in usual solid state physics, have remarkable properties which cannot be found in usual solid state systems. The project will create and investigate polarons in the crossover between single and many impurity atoms and study their properties, such as their self-localization.