The master equation describing non-equilibrium one-dimensional problem
s like diffusion limited reactions or critical dynamics of classical s
pin systems can be written as a Schrodinger equation in which the wave
function is the probability distribution and the Hamiltonian is that
of a quantum chain with nearest neighbor interactions. Since many one-
dimensional quantum chains are integrable, this opens a new field of a
pplications. At the same time physical intuition and probabilistic met
hods bring new insight into the understanding of the properties of qua
ntum chains. A simple example is the asymmetric diffusion of several s
pecies of particles which leads naturally to Hecke algebras and q-defo
rmed quantum groups. Many other examples are given. Several relevant t
echnical aspects like critical exponents, correlation functions, and f
inite-size scaling are also discussed in detail. (C) 1994 Academic Pre
ss, Inc