Exact Non-Stationary Probabilities in the Asymmetric Exclusion Process   on a Ring
  By a geometrical treatment of the Bethe ansatz, we obtain an exact solution for the totally asymmetric exclusion process on a ring. We derive an explicit determinant expression for the non-stationary conditional probability $Prob(x_1,...,x_P;t|x_1^0,...,x_P^0;0)$ of finding $P$ particles on sites $x_1,...,x_P$ at time $t$ provided they are on sites $x_1^0,...,x_P^0$ at time $t=0$. 
V.B. Priezzhev