On Some Generalizations of Batalin-Vilkovisky Algebras

We define the concept of higher order differential operators on a general noncommutative, nonassociative superalgebra A, and show that a vertex operator superalgebra has plenty of them, namely modes of vertex operators. A linear operator \Delta is a differential operator of order at most r if an inductively defined (r+1)-form \Phi_{\Delta}^{r+1} is identically zero. When A is supercommutative and associative and \Delta is an odd, square zero, second order differential operator on A, \Phi_{\Delta}^2 defines a "Batalin-Vilkovisky algebra" structure on A. We generalize this notion to any superalgebra with an odd, square zero, second order differential operator, and show that all properties of the classical BV bracket but one continue to hold "on the nose". We also point out connections to Leibniz algebras and the noncommutative homology theory of Loday. Taking the generalization process one step further, we remove all conditions on \Delta to examine the changes in the basic properties of the bracket. We see that a topological chiral algebra with a mild restriction yields a classical BV algebra in the cohomology. Finally, we investigate the quantum BV master equation and relate it to deformations of differential graded algebras.