Coherent Electron Control

经典力学告诉我们桥梁、汽车和日常生活中的其他物体是如何工作的。量子力学告诉我们微观世界中的电子、原子和其他物体是如何工作的。我们需要找到一种对自然的描述，它能在微观和宏观尺度以及两者之间的一切尺度上起作用。这是一个百年未解的问题，被称为“量子测量问题”。我们不仅想解决这个问题，而且想在更大的尺度上使用“量子性”，而不理解这个问题会阻止我们这样做。为了解决这个问题，需要研究介于微观和宏观之间的中间尺度的对象。这就是“相干电子控制”项目的目标。微观物体，电子，被放置在靠近日常世界物体，墙壁的地方，所以这两者如何相互作用的描述既不是量子力学描述的，也不是经典力学描述的。新的模型和理论可以通过这种方式进行测试。在实践方面，电子和墙壁之间的相互作用已经停止了基于电子的敏感设备的发展，称为电子干涉仪。这些墙破坏了电子有用的量子力学性质。如果能克服这种“退相干”，就能制造出新的电子器件，例如测量磁场的微小变化，从而在磁场起关键作用的众多技术领域中找到应用。纳米光栅的电子衍射将用于将电子束相干地分成两部分。墙壁将被放置在靠近电子束的地方，以部分地使电子束退相干。电子束重新组合，测量到的量子力学干涉量告诉我们退相干量。目前已有四种不同的微观理论得到验证。控制的消相干将探讨通过改变绝缘的氧化铜，半导体砷化镓，导电金，并与激光和粒子照射的墙壁。所获得的理解将被用来控制和减少退相干，并被应用于扩大现有的电子干涉仪的尺寸。用这种方法，试图建造世界上最大和最灵敏的电子干涉仪。将根据正在开发的新技术申请专利，这些发明可能会有市场。该研究项目为研究生、本科生和高中生提供自由电子量子光学新研究领域的经验。该奖项反映了NSF的法定使命，并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，被认为值得支持。

Classical Mechanics tells us how bridges, cars, and other objects in our everyday world work. Quantum Mechanics tells us how electrons, atoms and other objects in the microscopic world work. We need to find a description of nature that works at the microscopic and macroscopic scales and everything in between. This is a century-old unsolved problem that is called the "Quantum Measurement Problem." Not only do we want to solve the problem, but we want to use "quantumness" at a larger scale, and not understanding the problem stops us from doing this. To solve this problem objects at an intermediate scale, in between the microscopic and macroscopic, need to be studied. This is what the project: "Coherent Electron Control" is aiming to do. Microscopic objects, electrons, are placed close to an everyday world object, a wall, so that the description of how the two interact is neither described by Quantum Mechanics, nor Classical Mechanics. New models and theories can be tested in this way. On the practical side, the interaction between electrons and walls has stopped the development of sensitive devices based on electrons, called electron interferometers. The walls destroy the useful quantum mechanical properties of the electrons. If this "decoherence" can be overcome, new electron devices can be constructed that measure, for example, small changes in magnetic fields, and may thus find application in the numerous areas of technology where magnetic fields play a key role.Electron diffraction from nanofabricated gratings will be used to split electron beams coherently into two parts. Walls will be placed close to the electron beams to partially decohere the electron beams. The electron beams are recombined and the measured amount of quantum mechanical interference tells us about the amount of decoherence. Four different existing microscopic theories have now been tested. Control of the decoherence will be explored by changing the wall from insulating copper oxide, to semi-conducting Gallium Arsenide, to conducting gold, and illuminating the walls with laser light and particles. The understanding gained will be used to control and reduce the decoherence and be applied to enlarge the size of existing electron interferometers. In this way it is attempted to construct the largest and most sensitive electron interferometer in the world. Patents will be pursued based on the new technology being developed and the inventions may be marketable. The research project provides experience to graduate students, undergraduate students and high school students in the new research area of free electron quantum optics.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.