Trans-Planckian Scale and Krein Space Quantization
  In this work, Krein space quantization method is applied to eliminate the Ultraviolet divergence of Green functions. This paper shows that the power spectrum of scalar field fluctuations can be calculated in the limit of short distance physics, trans-Planckian physics, without using the usual re-normalization process. 
A. Sojasi and M. Mohsenzadeh
gr-qc