The paper studies the eigenstate of the inverse operators a-1 and (a+)-1 in Fock space, then educes the eigenstate of inverse operator a-1 and the eigenstate of inverse operator (a+)-1 is zero.
It is pointed out that the assertion that the eigenfunction of the creation operator a + is identically zero is not rigorous. On the contrary, the eigenfunction of a + may be discussed by using the contour integral representation of δ function, the property of which and the relation with the eigenstate of the annihilation operator are discussed. Its applications, especially the application in thoroughly studying the inverse operator's properties, are presented. It is shown that the phase operator can also be represented by the inverse operator.
The inverse of paraboson annihilation and creation operators is introduced. The properties of these operators, their number state representation and commutation relations are discussed. Also introduced are the family of eigenstates of bilinears in paraboson operators and their inverses; and study the nonclassical properties, namely, squeezing and fluctuations in number of parabosons in these eigenstates. It is observed that a family of the eigenstates of a+−1a is the parasqueezed vacuum, S(σ)‖0,α〉. Similarly, a family of the eigenstates of aa+−1 is the parasqueezed first state, S(σ)‖n=1,α〉.
A Fock representation of q-commutation relation is studied by constructing a q-Fock space as the space of the representation, the q-creation and q-annihilation operators (-1 < q < 1). In the case of 0 < q < 1, the q-Fock space is interpolated between the Boson Fock space and the full Fock space. Also, a unitary decomposition of the q-Fock space (q=0) is studied.