ΔI=4Bifurcation without Explicit Fourfold Symmetry

We demonstrate that $\Delta I=4\mathrm{}$ bifurcation can arise from the projected shell model without introducing explicitly either a $Y_{44}$ deformation or an $I^4$ term in the Hamiltonian. If band mixing through the usual two-body Hamiltonian is dominated by a single two-band mixture near the yrast line, a clear staggering can appear. Detailed investigation shows that this staggering is associated with interference effects in the rotation from intrinsic to laboratory coordinate systems.