The fluctuation formation of phase solitons in superconducting two-band bridges

Based on the Ginzburg–Landau theory, the dependence of the threshold energy $\delta F_{\operatorname{thr}}$ of formation of a phase slip center from the current for a superconducting two-band bridge has been calculated. It has been found that, in the case of sufficiently long bridges and a weak interband Josephson coupling, there is a range of currents at which fluctuation transition from the state of the zero interband phase difference to the states with a phase soliton is possible, which manifests itself in a considerable decrease in the threshold energy $\delta F_{\operatorname{thr}}$, and a fluctuation change in the number of phase solitons in the bridge. In the case of a strong interband coupling, no fluctuation formation of phase solitons occurs and the dependence $\delta F_{\operatorname{thr}}(I)$ tends to the expression obtained earlier by Langer and Ambegaokar for a single-band superconductor.