Title: On the response of a system with bound states of particles to the perturbation by the external electromagnetic field
Author(s):

	Yu.V.Slyusarenko (Akhiezer Institute for Theoretical Physics, NSC KIPT, 1 Akademicheskaya str., 61108 Kharkiv, Ukraine) ,
	A.G.Sotnikov (Akhiezer Institute for Theoretical Physics, NSC KIPT, 1 Akademicheskaya str., 61108 Kharkiv, Ukraine)

The response of the system, consisting of two types of opposite-charged fermions and their bound states (hydrogen-like atoms), to the perturbation by the external electromagnetic field in low particle kinetic energies region is studied. Investigations are based on using a new formulation of the second quantization method that includes a capability of forming the particle bound states [1]. Expressions for Green functions that describe the system response to the external electromagnetic field and take into account the presence of particle bound states (atoms) are found. Macroscopic parameters of the system, such as conductivity, permittivity and magnetic permeability in terms of these Green functions are found. As an example, the perturbation of the ideal hydrogen-like plasma by the external electromagnetic field in low temperature region is considered. Expressions for the values are found that describe the ideal gas of hydrogen-like atoms Bose-condensate response to the external electromagnetic field.

Key words: Green functions, bound states, response of systems, low-temperature hydrogen-like plasma, conductivity, magnetic permeability
PACS: 05.30.d, 05.30.Jp, 03.75.Mn, 03.75.Hh