多光子激发相干态的Wigner函数

Wigner函数的负性是非经典量子态的重要判据之一.利用Fock态表象下Wigner函数的一般表达式，重构了相干态｜z〉的k光子激发态｜+k，z〉～a^－k｜z〉（k≥1）的Wigner函数，并根据其数值结果讨论了该量子态的非经典特性（这里a^－1为Bose湮没算符的逆算符，其作用相当于Bose产生算符）.结果表明，不论k取奇数还是偶数，相干态的这些k光子激发态都具有非经典特性；而且k的取值越大，这些量子态的非经典特性越明显. 关键词： 非经典量子态 激发相干态 Wigner函数 非经典特性

Wigner functions of multiple-photon excited coherent states

Wigner functions in phase space are reconstructed for the excited coherent states, which are generated by applying the inverse of k-Boson operators repeatedly to the coherent states. The non-classicality of these states is discussed by calculating their Wigner functions in Fock-state space. Numerical results show that these excited coherent states always reveal non-classical characteristics.no matter whether the excited number k is even or odd, and also the corresponding non-classicality is more obvious with the number k increasing.