Superballistic wavepacket spreading in double kicked rotors

TL;DR

This paper explores superballistic wavepacket spreading in double kicked rotors, revealing conditions for cubic-time variance growth and highlighting the importance of system symmetry and KAM properties.

Contribution

It demonstrates superballistic spreading in double kicked rotors and identifies key factors influencing this behavior, advancing understanding of quantum wavepacket dynamics.

Findings

Wavepacket variance can grow as the cube of time.

Symmetry and KAM properties are crucial for spreading behavior.

Provides insights into exponential wavepacket spreading phenomena.

Abstract

We investigate possible ways in which a quantum wavepacket spreads. We show that in a general class of double kicked rotor systems, a wavepacket may undergo superballistic spreading; i.e., its variance increases as the cubic of time. The conditions for the observed superballistic spreading and two related characteristic time scales are studied. Our results suggest that the symmetry of the studied model and whether it is a Kolmogorov-Arnold-Moser system are crucial to its wavepacket spreading behavior. Our study also sheds new light on the exponential wavepacket spreading phenomenon previously observed in the double kicked rotor systems.