L. Accardi et al., A new algebra in the stochastic approximation for the model of a particle interacting with a quantum field, THEOR MATH, 116(3), 1998, pp. 1050-1062
When the stochastic approximation is used to calculate correlation function
s in the model of a particle interacting with a quantum field, a new algebr
a with temperature-dependent commutation relations appears. This algebra ge
neralizes the free (Boltzmann) algebra.