“…The operators of second quantization of quasi-particles ( a ì k , a + ì k ) and phonons ( b ì q , b + ì q ) satisfy the Bose commutative relationships. The renormalized spectrum of quasi-particles interacting with phonons at an arbitrary temperature (T), like in [23], is obtained from the poles of Fourier image of quasi-particle Green's function G( ì k, ω ′ ), which through the Dyson equation…”