MACROSCOPIC PHASE COHERENCE FROM SYNTHETIC INTERLAYER COUPLING IN VAN DER WAALS FLAT BANDS

非技术性描述：许多壮观的物理现象和有用的设备依赖于宏观量子相干。 最著名的例子是超导体，其中宏观相干性直接与电阻的不存在以及相干自由度的出现联系在一起，这些自由度构成了操纵量子信息的最佳开发平台的基础。然而，宏观量子相干，在原则上，一个更广泛的现象。该项目旨在实现宏观量子相干的新模式，在广泛的一类材料称为货车德瓦尔斯异质结构。 货车德瓦耳斯异质结构由连续层叠的二维原子晶体（如石墨烯）组成;它们的高结晶完整性和宽范围的可调谐性将各种新的量子相干态置于实验范围内。 通过实现以宏观量子相干为特征的新状态，该项目进一步理解了这些现象，并开辟了量子信息处理的新途径。 与研究工作的协同作用是一项专注于技术劳动力发展的教育计划，通过物理，化学和材料科学研究生暑期学校实施，研究量子科学相关问题。 技术描述：该项目的最终目标是在双层激子凝聚体中创建基于层间相干性的新型量子比特。 该位利用了预测在这些系统中发生的自发相位相干性。双层激子凝聚体，首先在半导体量子威尔斯中发现，最近被证明存在于石墨烯和硫属化物异质结构在较高的温度和要求较低的实验条件下，特别是在没有磁场。 该研究小组正在使用频率相关的层间隧穿光谱，通过AC约瑟夫森效应的激子模拟来直接检测宏观相位相干性的出现。 这种新的检测模式，然后允许在各种基于带结构工程的二维双层双层结构的宏观相干性的广泛搜索。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Non-technical description: Many spectacular physical phenomena—and useful device—rely on macroscopic quantum coherence. The most well known example are superconductors, where macroscopic coherence is directly tied both the absence of electrical resistance as well as the emergence of coherent degrees of freedom that form the basis for the best developed platforms for manipulating quantum information. However, macroscopic quantum coherence, in principle, a much broader phenomenon. This project aims to realize new modalities of macroscopic quantum coherence in a broad class of materials known as van der Waals heterostructures. Van der Waals heterostructures consist of successively laminated two dimensional atomic crystals such as graphene; their high crystalline perfection and broad range of tunability put a variety of new quantum coherent states in experimental range. By realizing new states characterized by macroscopic quantum coherence, this project furthers understanding of these phenomena and opens new avenues towards quantum information processing. Synergistic with the research effort is an educational initiative focused on technical workforce development, implemented through a summer school for graduate student across physics, chemistry and materials science working on quantum science related problems. Technical description:The ultimate goal of this project is to create a novel quantum bit based on interlayer coherence in a bilayer exciton condensate. This bit exploits the spontaneous phase coherence predicted to occur in these systems. Bilayer exciton condensates, first discovered in semiconductor quantum wells, have recently been shown to exist in graphene and chalcogenide heterostructures at higher temperatures and under less demanding experimental conditions—particularly in the absence of magnetic fields. The research team is using frequency-dependent interlayer tunneling spectroscopy to directly detect the emergence of macroscopic phase coherence through the excitonic analog of the AC Josephson effect. This new detection modality then allows a broad search for macroscopic coherence in a variety of double layer structures based on band-structure engineered two dimensional double layers.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.