Representations of Hecke algebras and the Alexander polynomial

We study a certain quotient of the Iwahori-Hecke algebra of the symmetric group Sd, called the super Temperley-Lieb algebra STLd. The Alexander polynomial of a braid can be computed via a certain specialization of the Markov trace which descends to STLd. Combining this point of view with Ocneanu's formula for the Markov trace and Young's seminormal form, we deduce a new state-sum formula for the Alexander polynomial. We also give a direct combinatorial proof of this result.