Developing coherent states as a resource in quantum technology

在量子力学中，场的强度和位相并不是同时以完美的精度定义的。在寻找描述光子关联的数学模型时，哈佛大学的罗伊·格劳伯提出了一种由光子数本征态叠加而成的量子态。他称这种量子状态为相干态，其相位和强度虽然在某种程度上是不确定的，但定义得相当清楚。自发现以来，相干态已经在所有物理系统中找到了一个位置，在这些系统中，量子物理涉及到快速发展的光学物理的实验情况。相干态是量子物理研究的重要资源。正是在相干态及其实验实现(理想的激光场)出现之后，才有可能对量子力学的概念基础进行实验测试。科学各个分支的最新进展导致了在原子水平上操纵性质--即量子工程--已经成为可能。相干态也是量子力学在信息处理和在量子水平上控制和操纵系统的应用中的重要资源。相干态是经典物理和量子物理之间的分界线。当振幅较大时，相干态的相位不确定性可以忽略不计，但当振幅较小时，相干态的相位不确定性很大。在这项研究中，我们想要找出相干态在控制和操纵量子系统中所起的作用以及它是如何做到的。这个项目的核心在于相干态的性质，它被定义为各种物理系统，如定常场、行波场、谐振子、固态系统和原子凝聚体。我们提出了四个主要的主题：1.将相干态作为一个光学跑动场进行操控。稳定相干态的操作和控制3.使用相干态探索量子世界和经典世界之间的边界4。相干态作为量子技术中的一种资源的能量来源的研究

In quantum mechanics, the intensity and phase of a field are not simultaneously defined with perfect precision. In searching for a mathematical model to describe photon correlations, Roy Glauber at Harvard University suggested a quantum state in a superposition of photon-number eigenstates. He called this quantum state, whose phase and intensity, although uncertain to some extent, are fairly well defined, a coherent state. Since its discovery, the coherent state has found a place in all physical systems where quantum physics is involved in the rapidly evolving experimental situations of optical physics. The coherent state is an important resource for the study of quantum physics. It was after the advent of the coherent state and its experimental realisation (an idealised laser field), that experimental tests of the conceptual foundations of quantum mechanics were possible. Recent advances in various branches of science have led to a situation where the manipulation of properties at the atomic level - that is, quantum engineering-has become feasible. The coherent state is also an important resource in applications of quantum mechanics for information processing and for the control and manipulations of a system at the quantum level. The coherent state, whose uncertainty in phase is negligible when the amplitude is large, but significant when the amplitude is small, serves as a boundary between classical and quantum physics. In this investigation we want to find out the roles played by the coherent state in the control and manipulation of a quantum system and how it is done. The core of this project lies in the properties of coherent states, which are defined for various physical systems, such as a stationary field, a travelling field, a harmonic oscillator, solid-state systems and atomic condensates. We propose to address four main topics:1. Manipulation of the coherent state as an optical running field.2. Manipulation and control of a stationary coherent state 3. Exploration of the boundary between quantum and classical worlds using coherent states4. Investigation of the origin of the power of coherent states as a resource in quantum technology