Studies of Lattice-Based Atomic Quantum Systems with Engineered Dissipation

这个项目的目标是了解和控制耦合到环境中的小量子系统的阻尼。量子力学是可逆的，也就是说，如果向前或向后播放量子系统的假想电影，它看起来是一样的。那么，如何在量子物理中出现不可逆的衰减呢？这个项目的目标是设计一个简单的模型系统，由一个“原子量子点”(一个人造原子)耦合到一个空真空中，这是所有环境中最简单的环境。这个可调的实验系统会发射物质波，而不是光辐射，它将允许随着环境结构的变化而精确地研究衰减。应该有可能使用大量规则间隔的原子量子点来建立类似激光的光源，并利用与环境的耦合来实现一种新的量子隧道形式，这可能会在固体现象的量子模拟中得到应用。虽然第一组实验揭示了量子力学衰减的本质，但第二组实验将调查是否可以避免由于大环境而造成的这种衰减。在这里，所考虑的模型系统将由一个原子以管状几何形式通过一维原子气体组成。碰撞应该会使原子减速并完全抑制其运动，但通过使环境有效透明来利用量子力学来屏蔽原子运动是可能的，这样就可以抑制衰减。发展控制耗散和衰减的方法对于量子模拟和量子信息科学是至关重要的，该项目的结果将对解决一些根本的挑战具有重要意义。该项目致力于在超冷原子物理背景下对新型耗散系统的实验研究，重点关注具有可控多体特征的玻色子环境中的工程化原子量子点和可移动杂质。这种系统的实现是通过使用具有超精细状态成分的超冷同核原子混合物来实现的，这些超精细状态成分由依赖于状态的光势独立控制。该项目的目标包括探索自发和超辐射物质波发射，探索由相干修饰产生的瞬逝物质波场引起的耦合，以及由超流环境的声子激发提供的耦合，以实现耗散量子伊辛链的前景。利用与一维玻色气体的耦合，该项目进一步旨在研究自由杂质在可积性附近的耗散和相干输运，并有望观察到新的多体效应。

The goal of this project is to understand and control the damping of small quantum systems coupled to an environment. Quantum mechanics is reversible, that is, a hypothetical movie of a quantum system looks the same if it is played forward or in reverse. So how can damping, something non-reversible, emerge in quantum physics? This project aims to engineer a simple model system consisting of an "atomic quantum dot" (an artificial atom) coupled to an empty vacuum, the simplest of all environments. This tunable experimental system, which emits matter waves rather than optical radiation, will allow for precise investigation of damping as the structure of the environment is changed. It should be possible to build laser-like sources using a large number of regularly spaced atomic quantum dots, and to exploit the coupling to the environment for a novel form of quantum tunneling, which may find use in quantum simulation of solid-state phenomena. While this first set of experiments sheds light on the nature of quantum mechanical damping, a second set of experiments will investigate whether such damping due to a large environment can be avoided. Here, the model system considered will consist of an atom moving through a one-dimensional atomic gas in a tube-like geometry. Collisions should slow down the atom and damp its motion completely, but it may be possible to harness quantum mechanics to shield the atomic motion by rendering the environment effectively transparent, such that damping is suppressed. Developing ways to control damping and dissipation are of paramount importance for quantum simulation and quantum information science, and the results of this project will be of relevance in addressing some of the fundamental challenges.The project is devoted to the experimental study of novel dissipative systems in the context of ultracold atomic physics, focusing on engineered atomic quantum dots and mobile impurities coupled to a bosonic environment with controllable many-body character. The implementation of such systems is made possible through the use of ultracold, homonuclear atomic mixtures with hyperfine-state components that are independently controlled with state-dependent optical potentials. The project goals include an exploration of spontaneous and superradiant matter-wave emission, of couplings induced by evanescent matter-wave fields arising from coherent dressing, as well as couplings provided by phononic excitations of a superfluid environment, with the prospect of realizing a dissipative quantum Ising chain. Exploiting the coupling to one-dimensional Bose gases, the project furthermore aims to investigate dissipative and coherent transport for unconfined impurities near integrability, with the prospect of observing novel many-body effects.