  Low-lying collective excitations in even-even vibrational and transitional
nuclei may be described semi-classically as quadrupole running waves on the
surface of the nucleus ("tidal waves"), and the observed vibrational-rotational
behavior can be thought of as resulting from a rotating condensate of
interacting $d$ bosons. These concepts have been investigated by measuring
lifetimes of the levels in the yrast band of the $^{102}$Pd nucleus with the
Doppler Shift Attenuation Method. The extracted $B(E2)$ reduced transition
probabilities for the yrast band display a monotonic increase with spin, in
agreement with the interpretation based on rotation-induced condensation of
aligned $d$ bosons.
