Interferometric information gain versus interaction-free measurement
Interferometric information gain versus interaction-free measurement
复制标题
干涉测量信息增益与无交互测量
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
K. Svozil
中科院分区：
文献类型：
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作者：
Gunther Krenn;J. Summhammer;K. Svozil
与理想的马赫-曾德尔干涉仪的相互作用自由的测量方案承诺区分吸收样品的平均吸收比简单的传输方案。我们表明，这是唯一正确的两种样品，其中一种是高度吸收和其他是高度透射的合奏。一旦引入具有中间透射率的第三种样品，但不允许相移，则在干涉方案中，样品中被吸收粒子的信息增益的成本更高。我们还调查了一般情况下的样品具有连续范围的传输和相移值，这样的干涉仪的测量两个样品特性的能力可以被利用。使用干涉仪，主要可区分的样品的数量随着探测粒子的数量线性增加，但是使用简单的传输设置，它作为平方根增加。当希望用干涉方案从连续样品分布中区分两倍多的样品时，每个样品的吸收颗粒的数量仅加倍，但用简单的透射方案则是四倍。
Interaction-free measurement schemes with ideal Mach-Zehnder interferometers promised to distinguish absorptive samples with lower average absorption than simple transmission schemes. We show that this is only true for an ensemble of two kinds of samples, where one kind is highly absorptive and the other is highly transmissive. As soon as a third kind of sample with intermediate transmission is introduced, but no phase shift is permitted, the cost of information gain in terms of absorbed particles in the samples is higher in the interferometric scheme. We also investigate the general case of samples with a continuous range of transmission and phase shift values, such that an interferometer’s ability to measure both sample characteristics can be exploited. With an interferometer the number of principally distinguishable samples increases linearly with the number of probe particles, but with a simple transmission setup it increases as the square root. When wishing to distinguish twice as many samples from a continuous sample distribution with an interferometric scheme, the number of absorbed particles per sample only doubles, but it quadruples with a simple transmission scheme.