增、减光子压缩真空态的维格纳函数及其非经典特性

Wigner Functions of Photon-added and-subtracted Squeezed Vacuum States and Their Non-classical Properties

利用Fock态表象下的维格纳(Wigner)函数表示式,重构增、减光子压缩真空态的维格纳函数;依据维格纳函数在相空间中的分布规律,讨论这些量子态的非经典特性.数值结果表明:增、减光子压缩真空态的维格纳函数均出现负值,它们都是具有非经典特性的量子态;这些量子态的维格纳函数与增、减光子数k的取值有关,k取奇数时函数的负性明显大于k取偶数时的状况.此结果为这些量子态的测量提供理论依据.

Based on the expressions of Wigner functions in Fock-spaces,we reconstruct the Wigner functions of photon-added and-subtracted states of squeezed vacuum states.Negativities of these Wigner functions numerically indicate that these states are really non-classical quantum states.We also discuss how these negativities depend on the photon number k added to and subtraced from the squeezed vacuum states.The negativities are greater when k is odd numbers than those when k is even numbers.The result provides a theoretical foundation for measuring these states.