Structures of (supersymmetric) classical W-algebras

Abstract

In the first part of this paper, we discuss the classical W-algebra $\mathcal{W}(\mathfrak{g},F)$ associated with a Lie superalgebra $\mathfrak{g}$ and the nilpotent element $F$ in an ${\mathfrak{sl}}_2$-triple. We find a generating set of $\mathcal{W}(\mathfrak{g},F)$ and compute the Poisson brackets between them. In the second part, which is the main part of the paper, we discuss supersymmetric classical W-algebras. We introduce two different constructions of a supersymmetric classical W-algebra $\mathcal{W}(\mathfrak{g},f)$ associated with a Lie superalgebra $\mathfrak{g}$ and an odd nilpotent element $f$ in a subalgebra isomorphic to $\mathfrak{osp}(1|2)$. The first construction is via the SUSY classical BRST complex and the second is via the SUSY Drinfeld-Sokolov Hamiltonian reduction. We show that these two methods give rise to isomorphic SUSY Poisson vertex algebras. As a supersymmetric analogue of the first part, we compute explicit generators and Poisson brackets between the generators.