Thermodynamic Integration Methods, Infinite Swapping and the Calculation   of Generalized Averages
  In the present paper we examine the risk-sensitive and sampling issues associated with the problem of calculating generalized averages. By combining thermodynamic integration and Stationary Phase Monte Carlo techniques, we develop an approach for such problems and explore its utility for a prototypical class of applications. 
J. D. Doll, P. Dupuis, P. Nyquist
cond-mat.stat-mech