$q$-Fock Space of $q$-Analytic Functions and its realization in $L^{2}(\mathbb{C}; e^{-z\bar z} \,\mathrm{d}x\,\mathrm{d}y)$
Amedeo Altavilla, Swanhild Bernstein, Martha Lina Zimmermann
TL;DR
We develop a geometric $q$-deformation of the Fock space of holomorphic functions on $\mathbb{C}$ via $q$-analyticity, introducing $z_q^n$ and the Hilbert space $\mathcal{F}_q(\mathbb{C})$ with basis $\{z_q^n/\sqrt{[n]_q!]\}$. The reproducing kernel and a $q$-position/$q$-momentum pair with deformed commutation relations are established, and a unitary $q$-Bargmann transform realizes $\mathcal{F}_q(\mathbb{C})$ as a subspace of $L^2(\mathbb{C}; e^{-|z|^2}dxdy)$ via complex Hermite expansions. A complete bidimensional framework is developed through a tensor Bargmann transform $\mathcal{B}_q^{(2)}$, identifying $\{z_q^k\overline{z}_q^h\}$ with the corresponding basis in $L^2$ and yielding a coherent-state kernel $A^{(2)}$. Overall, the work provides a geometric-analytic approach to $q$-function theory that complements operator-theoretic models like ACKS, and it builds a unitary correspondence between $q$-Hermite data and $q$-analytic monomials.
Abstract
We introduce a $q$-deformation of the Fock space of holomorphic functions on $\mathbb{C}$, based on a geometric definition of $q$-analyticity. This definition is inspired by a standard construction in complex differential geometry. Within this framework, we define $q$-analytic monomials $z_q^n$ and construct the associated $q$-Fock space as a Hilbert space with orthonormal basis $\{z_q^n/\sqrt{[n]_q!]}\}_{n\ge 0}$. The reproducing kernel of this space is computed explicitly, and $q$-position and $q$-momentum operators are introduced, satisfying $q$-deformed commutation relations. We show that the $q$-monomials $z_q^n$ can be expanded in terms of complex Hermite polynomials, thereby providing a realization of the $q$-Fock space as a subspace of $L^2(\mathbb{C}; e^{-|z|^2}\,\mathrm{d}x\,\mathrm{d}y)$. Finally, we define a $q$-Bargmann transform that maps suitable $q$-Hermite functions into our $q$-Fock space and acts as a unitary isomorphism. Our construction offers a geometric and analytic approach to $q$-function theory, complementing recent operator-theoretic models.
