A realization of certain modules for the $N=4$ superconformal algebra and the affine Lie algebra $A_2 ^{(1)}$

Abstract

We shall first present an explicit realization of the simple $N=4$ superconformal vertex algebra $L_{c} ^{N=4}$ with central charge $c=-9$. This vertex superalgebra is realized inside of the $ b c \beta \gamma $ system and contains a subalgebra isomorphic to the simple affine vertex algebra $L_{A_1} (- \tfrac{3}{2} \Lambda_0)$. Then we construct a functor from the category of $L_{c} ^{N=4}$--modules with $c=-9$ to the category of modules for the admissible affine vertex algebra $L_{A_{2} } (-\tfrac{3}{2} \Lambda_0)$. By using this construction we construct a family of weight and logarithmic modules for $L_{c} ^{N=4}$ and $L_{A_{2} } (-\tfrac{3}{2} \Lambda_0)$. We also show that a coset subalgebra of $L_{A_{2} } (-\tfrac{3}{2} \Lambda_0)$ is an logarithmic extension of the $W(2,3)$--algebra with $c=-10$. We discuss some generalizations of our construction based on the extension of affine vertex algebra $L_{A_1} (k \Lambda_0)$ such that $k+2 = 1/p$ and $p$ is a positive integer.