Airy wavepackets are Perelomov coherent states

Accelerating non-spreading wavepackets in a nonrelativistic free-particle system, with probability distribution having an Airy function profile, were discovered by Berry and Balazs [Am. J. Phys. 47(3), 264–267 (1979)], and have been subsequently realised in several optics experiments. It is shown that these wavepackets are actually Perelomov coherent states. It is found that the Galilean invariance of the Schrödinger equation plays a key role in making these states unique and gives rise to their unusual propagation properties.