Koornwinder polynomials and the stationary multi-species asymmetric   exclusion process with open boundaries
  We prove that the normalisation of the stationary state of the multi-species asymmetric simple exclusion process (mASEP) is a specialisation of a Koornwinder polynomial. As a corollary we obtain that the normalisation of mASEP factorises as a product over multiple copies of the two-species ASEP. 
Luigi Cantini, Alexandr Garbali, Jan de Gier and Michael Wheeler
math-ph cond-mat.stat-mech math.CO math.MP