Quantum phenomena in hybrid systems: Interfacing engineered materials and nanostructures with atomic systems

在过去的十年中，量子光学领域实现了对冷离子、冷原子甚至室温氮空位中心(NV)等原子系统的多粒子量子态的令人印象深刻的控制--在钻石晶体中表现为类似原子的系统。与此同时，基于电子的固态系统，如超导系统和量子点，已经达到了控制和设计相互作用的水平，以至于它们可以与原子系统相媲美。对于基础科学和21世纪的技术应用，我们的目标是杂交，其中原子和固态系统是耦合的。原子芯片是芯片表面的电子电路与位于其上方的孤立的原子系统耦合的器件。这种耦合已经产生了大量关于原子系统和电子系统的有价值的见解。我们计划进入新的制度，在那里原子-电子耦合是在新类型的界面上启动的，导致对每个系统的新见解，并最终在它们之间实现相干(量子)耦合-在电子的量子自由度也受到控制的情况下。“常规”感兴趣的表面可能包括“抗噪声”材料和几何结构、工程范德华表面、等离子体导轨以及微波谐振器和波导器，而“量子表面”可能包括亚散粒噪声电流、持续电流、超导体(SC)涡旋、磁通门、单电子自旋或由几个电子组成的电流。实验将根据提议中描述的详细理论贡献来设计和解释。我们将使用由传感器系统的选择定义的三种配置的原子芯片：其中一种由冷单个离子、离子晶体或从陷阱中喷出并自由飞行的离子组成，第二个由冷原子组成，第三个由NV的单个或整体组成。每一种系统都有自己的优势。冷离子具有较长的相干时间，单粒子易于观察和操纵。离子在深势中提供了非常长的捕获时间。即使在玻色-爱因斯坦凝聚态下，冷原子也可能被带到离地表更近的地方。NV的位置可能会更近，距离表面几纳米。此外，自由飞行时喷出的离子可以接近纳米尺度的表面。因此，覆盖了从几十微米到亚微米和纳米的全范围。预计最终这三种构型中的每一种都将被证明对特定的实验制度(包括基本洞察力和技术)都是有利的，它们共同将能够呈现原子-电子耦合所涉及的基本物理和势的全面图景。

In the last decade the field of quantum optics achieved impressive control over the multi-particle quantum state of atomic systems such as cold ions, cold atoms and even room temperature nitrogen vacancy centers (NVs) - behaving as atom-like systems in a diamond crystal. In parallel, solid state systems based on electrons e.g. superconducting systems and quantum dots, have reached such a level of control and engineered interactions that they are rivaling atomic systems. For fundamental science and 21st century technological applications we aim for hybridization, where atomic and solid state systems are coupled. Atom Chips are devices in which electron-based circuits on chip surfaces are coupled to isolated atomic systems positioned above. Such coupling has already given rise to a huge influx of valuable insight both on the atomic system and on the electron system. We plan advancing into new regimes where atom-electron coupling is initiated in novel kinds of interfaces leading to new insight on each of the systems and finally to a coherent (quantum) coupling between them - in situations where the electron quantum degrees of freedom are also under control. A "regular" surface of interest may include "anti-noise" materials and geometries, engineered van der Waals surfaces, plasmonic guides, as well as MW resonators and wave guides, while a "quantum surface" may include sub shot-noise currents, persistent currents, superconductor (SC) vortices, a flux gate, a single electron spin, or a current made of few electrons. Experiments will be designed and interpreted by the detailed theoretical contributions described in the proposal.We will utilize Atom Chips in three configurations defined by the choice of the sensor system: One of them consists of cold single ions, ion crystals or ions ejected from a trap and in free-flight, the second an ensemble of cold atoms and the third single or ensembles of NVs. Each system has its own advantages. The cold ions have long coherence times and single particles can be easily observed and manipulated. Ions provide very long trapping times in deep potentials. The cold atoms may be brought much closer to the surface - even in a Bose-Einstein condensed state. The NVs may be positioned still much closer, at distances of several nano-meters from a surface. Also ejected ions in free-flight may approach a surface at the nm scale. Thus, the full range from tens of microns down to sub-microns and nano-meters is covered. It is expected that eventually each of the three configurations will prove advantageous for specific experimental regimes (both for fundamental insight and technology) and that together they will be able to present a comprehensive picture of the underlying physics and potential involved in the atom-electron coupling.