Bogolubov transformation

The results derived earlier can be written via a Bogolubov transformation introduced by... 

The effect of thermal pion fluctuations on the specific heat and the neutrino emissivity of neutron stars was discussed in [27, 28] together with other in-medium effects, see also reviews [29, 30], Neutron pair breaking and formation (PBF) neutrino process on the neutral current was studied in [31, 32] for the hadron matter. Also ref. [32] added the proton PBF process in the hadron matter and correlation processes, and ref. [33] included quark PBF processes in quark matter. PBF processes were studied by two different methods with the help of Bogolubov transformation for the fermion wave function [31, 33] and within Schwinger-Kadanoff-Baym-Keldysh formalism for nonequilibrium normal and anomalous fermion Green functions [32, 28, 29],... 

In order to calculate the correlation functions, the Hamiltonian H has to be brought to the canonical form. This is done in two steps. First, we perform a two-component Bogolubov transformation in order to eliminate the cross-terms with opposite momenta,... 

In turn, the field operator (63), representing the field counterpart of (41), can be diagonalized by the following Bogolubov-type [80] canonical transformation [46]... 

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