截头相干态及其量子统计性质

Truncated Coherent States and Their Quantum Statistical Properties

本文引入一类新的量子光场态｜α，ｍ＞，称截头相干态（ｔｒｕｎｃａｔｅｄｃｏｈｅｒｅｎｔｓｔａｔｅｓ），它由Ｇｌａｕｂｅｒ相干态的数态展开式中去掉前面ｍ－１个（ｍ＝０，１，２，…）数态后所剩部分构成，即｜α，ｍ＞＝Ａｍ∑∞ｎ＝ｍαｎｎ！｜ｎ＞，Ａｍ是归一化常数．我们研究了这些态的量子统计性质，预言了一种与相干态具有相同的一、二阶相干度但不同的高阶相干度的光．我们也将截头相干态与文献中提出的与其具有相同数态结构的添加光子相干态（ｐｈｏｔｏｎａｄｄｅｄｃｏｈｅｒｅｎｔｓｔａｔｅｓ）的有关性质作了比较．截头相干态相当于对Ｇｌａｕｂｅｒ相干态作“切片”式解剖探查，这给我们了解相干态结构与性质之间的关系提供了新的一瞥。

We introduce a new class of states denoted by |α,m> , which is called truncated coherent states and consists of the number state expansion of a coherent state with the first m terms being truncated, i.e. |α,m>=A m∑∞n=mα nn!|n> , where A m is the normalization constant. We study the quantum statistical properties of such states and predict a sort of light that has the same first-and second order coherence as coherent states do but different higher than second order coherence from the latter. We also compare such new states in some properties with photon added coherent states previously proposed in literature. This treatement of a coherent state amounts to make out sections of a coherent state for microscopic examination and will give us a new insight into the relationship between structure and properies of coherent states. Analysis of the results obtained from studing the truncated coherent states is belived to deepen our understanding of wave particle duality and non classicality of light.