领头项奇偶相干态

Leading-Terms Even and Odd Coherent States

奇相干态只呈现反群聚而绝无压缩，偶相干态正好与之相反，只有压缩而无反群聚性。为了从内部窥视一下奇偶相干态的这种独特的非经典性是怎样产生的，我们引入一类新的量子光场态——领头项奇仍相干态。通过对这些量干态的研究，清楚地揭示出随着领头项奇偶相干态中项数的增多，它们的性质是怎样趋于奇偶相干态的。我们发觉，专偶相干态的典型性质实际上主要是由前面少数几个数态项决定的，特别是偶相干态的最大压缩实际上仅用前面三项的叠加即可得到，因此在实际中可用适当的领头项奇偶相干态来代替奇仍相干态。

Leading-terms even and odd coherent states, which consist of the first terms innumber-state expansion of even and odd coherent states, are introduced in this paper inorder to see, from internal structure of even and odd coherent states, how to come to beingthe typicaI non-classical properties that even coherent states exhibit only squeezing butno antibunching at all and, in contrast to this, odd coherent states have only antibunchingbut no squeezing- Present work clearly shows how quickly the behavior of leadingtermseven and odd coherent states approaches that of even and odd coherent states as thenumber of number states increases. It is found that the typical properties of even and oddcoherent states strongly depend on a few first terms, and therefore leadingterms even andodd coherent states with proper number of terms can be used to replace even and oddcoherent states for some practical reasons.