Phase transition in two-dimensional multicomponent Bose liquid: a new type of quasi-long-range order

The $\nu$-component two-dimensional (2D) Bose liquid is considered. It is shown that the finite temperature phase transition exists in this 2D continuously degenerate multicomponent system. The new type of quasi-long-range order occurs as a result of this transition. The correlation function in ordered state is a product of the power-law XY-universality class type function and the exponential function corresponding to the $SU(\nu)$ invariant model. The transition temperature is calculated for the diluted system. It is found that the physical mechanism of the phase transition is changed when $\nu$ exceeds the critical value $\nu_c = 4$. The experimental realization of the considered model is discussed briefly.