A formula for the Jack super nabla operator

Abstract

We study a Jack analog $\nabla(\mathbf{p},\mathbf{q})$ of the super nabla operator recently introduced by Bergeron, Haglund, Iraci and Romero for Macdonald polynomials. We prove that $\nabla(\mathbf{p},\mathbf{q})$ has a differential expression in the power-sum basis given in terms of Chapuy-Dołe\k{}ga and Nazarov-Sklyanin operators. This result is obtained from a more general formula for the operator $G(\mathbf{p},\mathbf{q})$ encoding the structure coefficients of Jack characters, from which $\nabla(\mathbf{p},\mathbf{q})$ is obtained by taking the top homogeneous part. A key step of the proof involves establishing that Chapuy-Dołe\k{}ga operators together with a dehomogenized version of Nazarov-Sklyanin operators have a Heisenberg algebra structure. The proof also uses a characterization of the operator $G(\mathbf{p},\mathbf{q})$ with a family of differential equations, recently established by the author.