Dynamical upper bounds on wavepacket spreading

Rowan Killip*, Alexander Kiselev, Yoram Last

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

43 Scopus citations


We derive a general upper bound on the spreading rate of wavepackets in the framework of Sohrödinger time evolution. Our result consists of showing that a portion of the wavepacket cannot escape outside a ball whose size grows dynamically in time, where the rate of this growth is determined by properties of the spectral measure and by spatial properties of solutions of an associated time-independent Schrödinger equation. We also derive a new lower bound on the spreading rate, which is strongly connected with our upper bound. We apply these new bounds to the Fibonacci Hamiltonian - the most studied one-dimensional model of quasicrystals. As a result, we obtain for this model upper and lower dynamical bounds establishing wavepacket spreading rates which are intermediate between ballistic transport and localization. The bounds have the same qualitative behavior in the limit of large coupling.

Original languageAmerican English
Pages (from-to)1165-1198
Number of pages34
JournalAmerican Journal of Mathematics
Issue number5
StatePublished - Oct 2003


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