Low-frequency asymptotics of Green functions for superfluid Bose-systems

A method permitting to find low-frequency asymptotics of Green functions for superfluid Bose-liquid without using fictitious external sources is developed. The structure of general Green functions Gsub(ab)sup(+-)(k vector, ω) in the range of small ω and k vector and at vsub(n) vector - vsub(s) vector not equal to 0 is found. The structure of Green functions peculiarities due to the existence of the first and second sound depends considerably on commutativity of operators a vector and b vector, determining the Green function, with operator of the mass M. The method developed of the study of low-frequency asymptotics of Green functions of superfluid systems can be also applied when considering similar problems for other systems with spontaneously distorted symmetry