Quantum Coherence

量子相干性

• 批准号: 0140377
• 负责人: Yakir Aharonov
• 金额: $ 27万
• 依托单位: University South Carolina Research Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-01 至 2005-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0140377&HistoricalAwards=false
• 关键词: Quantum; Coherence

A fundamental aspect of quantum phenomena is the non-local coherence of thequantum wave that describes the state of a particle, which is called thewave-particle duality. A consequence of this is the Heisenberg uncertaintyprinciple according to which there is a minimum to the product of theuncertainties of the position and momentum or time and energy of the particlethat is given by the Planck's constant. We plan to investigate the latteruncertainty principle in relation to the general relativistic gravitationalfield, using our earlier work that obtains this uncertainty relation using onlymeasurements intrinsic to the system under investigation. We shall also use newnon-local quantities that we have introduced, called modular variables, to studythe non-local quantum coherence of the wave function. This will be used toinvestigate the Aharonov-Bohm effect (discovered by the PI), which is thenon-local interaction of the wave function with the electromagnetic field. Somenew aspects of scattering due to the Aharonov-Bohm effect will be studied. Thelatter work is relevant to a wide class of problems involving surface waves andpolarized light propagating in optical fibers, where various impurities may bepresent.The quantum coherence of the wave function also opens up the possibilities forsecure communication using quantum systems and the construction of a quantumcomputer. Computations which would take a present state-of-the-art computer morethan the life-time of the universe to do would be done in less than a second bya quantum computer. We shall try to use the weak measurement, discovered by thePI, to obtain better quantum communication. We shall also try to use the geometric phase discovered by the PI and a co-PI towards constructing a quantumcomputer.

量子现象的一个基本方面是描述粒子状态的量子波的非局域相干性，这被称为波-粒子二元性。由此产生了海森堡不确定原理，根据该原理，由普朗克常数给出的粒子的位置和动量或时间和能量的不确定度的乘积最小。我们计划研究与一般相对论引力场有关的后一种测不准原理，利用我们以前的工作，只使用被研究系统的固有测量来获得这种测不准关系。我们还将使用我们引入的新的非局域量，称为模变量，来研究波函数的非局域量子相干性。这将被用来研究Aharonov-Bohm效应(由PI发现)，它是波函数与电磁场的非局域相互作用。由Aharonov-Bohm效应引起的散射的一些新的方面将被研究。后者涉及一大类问题，涉及表面波和偏振光在光纤中的传播，其中可能存在各种杂质。波函数的量子相干性也为使用量子系统进行保密通信和构建量子计算机打开了可能性。目前最先进的计算机需要比宇宙的整个生命周期更长的时间来完成计算，而量子计算机只需不到一秒的时间就可以完成。我们将尝试利用PI发现的弱测量来获得更好的量子通信。我们还将尝试使用PI和共同PI发现的几何相位来构建量子计算机。