数理解析研究所講究録
Graphical representations of the $q$-creation and the $q$-annihilation operators and set partition statistics (Infinite Dimensional Analysis and Quantum Probability Theory)
Hiroaki Yoshida
Abstract
In this note, we introduce acertain graphical representations of the $q$-creation the $q$-annihilation, the $q$-numb er, and the scalar operators on the $q$-Fock space.These are given as the cards on which some flow lines are drawn and increasing and decreasing of the number of lines correspond to creation and annihilation, respectively.By the cards arrangement technique with these cards, of which machinery is the same as of the partition function for the lattice spins model in statistical me- chanics, we write the moments of the $q$-Poisson random variable using the number of arc crossings, which is the same set partition statistic as restricted crossings investigated by P. Biane.This result suggests another $q$-deformed moments-cumulants relations, which interpolates between the usual and the free cases exactly.This is the joint work with Naoko Saitoh at Ochanomizu University.1The $q$ -Fock space For aHibert space 7{ and $q\in(-1,1)$ , the $q$-Fock space $\mathcal{F}_{q}(\mathcal{H})$ can be defined as follows: (see, for instance, [BS1], [BKS]) Let $\mathcal{F}^{fin}(\mathcal{H})$ be the linear span of vectors of the form $\xi_{1}\otimes\cdots\otimes\xi_{n}\in \mathcal{H}^{\otimes n}$ , where $n$ varies in $\mathrm{z}_{\geq 0}$ and we put $\mathcal{H}^{\otimes 0}\cong \mathrm{C}\Omega$ for some distinguished vector $\Omega$ called vacuum.We consider the sesquilinear form $\langle\cdot|\cdot\rangle_{q}$ on $\mathcal{F}^{J^{jn}}(\mathcal{H})$ given by the sesquilinear extension of $\langle\xi_{1}\otimes\cdots\otimes\xi_{n}|\eta_{1}\otimes\cdots\otimes\eta_{m}\rangle_{q}=\delta_{n,m}\sum_{\pi\in S_{n}}q^{i(\pi)}\langle\xi_{1}|\eta_{\pi(1)}\rangle\cdots\langle\xi_{n}|\eta_{\pi(n)}\rangle$ ,