T. Michoel, A. Verbeure
Goldstone Boson Normal Coordinates in Interacting Bose Gases
(74K, Latex2e)
ABSTRACT. For the phenomenon of Bose-Einstein condensation we construct the
canonical pair of field operators of the Goldstone Bosons explicitly
as fluctuation operators in the ground state. We consider the imperfect
Bose gas as well as the weakly interacting Bose gas. We prove that a
canonical pair of fluctuation operators is always related to the order
parameter and the generator of the broken symmetry fluctuations. We find
that although the first one has an anomalous behaviour, the second one
is squeezed by the same inverse rate. Furthermore we prove that this
canonical pair separates from the other variables of the system and that
it behaves dynamically as oscillator variables. Finally the long
wavelength behaviour of the spectrum determines the lifetime of this
pair.