New Journal of Physics

Free temporal evolution of a superbandwidth wave packet: the quantum tale of the hare and the tortoise

Enrique G. Neyra, Marcelo F. Ciappina, Lorena Rebón

Published Apr 1, 2026• 0 citations

Abstract

Abstract Can the interplay between quantum mechanics and classical optics offer new perspectives on wave packet dynamics? Building on this connection, we show that local momenta exhibiting both superoscillatory and suboscillatory characteristics can arise during the free propagation of a quantum particle. This behavior is mathematically analogous to the propagation of a superbandwidth laser pulse in a dispersive medium, where the instantaneous frequencies of the electric field locally exhibit similar sub- and superoscillatory features. This analogy is rooted in the equivalence between the wave description of light in classical optics and the formalism of quantum mechanics. In addition, we explore the phenomenon of wave packet localization during free propagation within a bounded region. This localization is directly linked to the distribution of local momenta within the confined wave packet region. To complement our quantum mechanical analysis, we also perform a classical analysis to provide further insights into this phenomenon. Our findings reveal that both the emergence of local momenta with sub- and superoscillatory features and the wave packet localization occur within a distinct timescale, which we define as the interference time .

DOI: 10.1088/1367-2630/ae5ac7

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