Experimental Study of Quantum Jumps with a Single Trapped Ion

量子理论成为世纪科学最重要的发展和胜利之一。目前，随着量子计算和其他量子技术的出现，“第二次量子革命”正在进行中。然而，量子理论的许多概念和想法仍然是神秘的或知之甚少。其中一个概念就是所谓的“波函数的坍缩”。“根据量子力学，微观物体如原子的行为就像波，它们可以同时存在于两种状态的叠加中。这就像著名的薛定谔的猫在盒子里，既死又活。然而，根据量子力学，这些叠加是无法观测到的：当进行观测时，叠加会“坍缩”到其中一个状态。当我们打开盒子时，我们看到的是一只猫是死的还是活的，而不是两者同时存在。该项目旨在研究量子力学崩溃的细节，使用单原子，一些最原始的量子粒子。单个原子将被电磁场捕获，并用激光控制，以引发量子坍缩并了解更多关于其性质的信息。理解量子坍缩的本质对于量子力学作为理论的基础以及量子计算和量子信息的实际方面都很重要。量子计算和量子通信等量子技术有望提高计算速度，改善信息安全，并为能源转换，电子和生物医学应用开发更好的材料。量子跃迁在1913年由Niels Bohr首次提出理论，但直到1986年才被Hans Dehmelt的团队在实验中观察到。在最初的实验中，跳跃表现为一个被捕获的激光冷却离子从“亮”状态到“暗”状态的瞬时跃迁，这是由光子计数探测器测量的。最近对超导电路构建的人造原子中的量子跳跃的观察使耶鲁大学的研究人员能够在一个实验中“捕捉”和“逆转”跳跃，这个实验是由超导量子比特发射的几乎每一个光子都被检测到的事实实现的。该项目计划使用一种新型的离子阱从单个捕获离子实现相同或更高水平的单光子检测，该离子阱包含一个椭圆镜，覆盖离子周围90%以上的立体角。这将使我们能够在纳秒时间尺度上观测到没有耗散的系统中的量子跳跃，并有可能跟踪和控制波函数坍缩的动力学。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Quantum theory became one of the most important developments and triumphs of the 20th century science. Currently, the “second quantum revolution” is underway with the advent of quantum computing and other quantum technologies. Yet, many concepts and ideas of quantum theory remain mysterious or poorly understood. One such concept is the so-called "collapse of the wave function." According to quantum mechanics, microscopic objects such as atoms behave like waves, and they can exist in superpositions of two states at once. This is like the famous Schrodinger’s cat in the box that is both dead AND alive at the same time. However, according to quantum mechanics, these superpositions cannot be observed: when an observation is made, the superposition “collapses” to one of the states. When we open the box, we observe a cat that is dead OR alive, not both at the same time. This project aims to study the minute details of quantum mechanical collapse using single atoms, some of the most pristine quantum particles. Single atoms will be trapped by electromagnetic fields and controlled with lasers to incite quantum collapse and learn more about its properties. Understanding the nature of quantum collapse is important both for the foundations of quantum mechanics as a theory, and for the very practical aspects of quantum computing and quantum information. Quantum technologies such as quantum computing and quantum communications promise faster computing speed, improved information security, and development of better materials for energy conversion, electronics, and biomedical applications. Quantum jumps were first theorized in 1913 by Niels Bohr, but it wasn’t until 1986 that they were observed experimentally by Hans Dehmelt’s group. In the original experiment, the jumps manifested themselves as instantaneous transitions of a single trapped, laser-cooled ion from the “bright” state to the “dark” state as measured by a photon-counting detector. More recent observations of quantum jumps in artificial atoms built from superconducting circuits allowed the researchers at Yale to “catch” and “reverse” the jumps in an experiment that was enabled by the fact that nearly every single photon emitted by the superconducting qubit was detected. This project plans to achieve the same or higher level of single photon detection from a single trapped ion using a novel ion trap that incorporates an elliptical mirror covering more than 90% of the solid angle around the ion. This will enable observing of the quantum jumps at the nanosecond time scale in a system that is free from dissipation, with the possibility to track and control the dynamics of the wave function collapse.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.