Ion traps are promising architectures for implementing quantum computers, but they suffer from excessive "anomalous" ion motional heating that limit their overall coherence and practicality for scalable quantum computing. The exact microscopic origins of anomalous heating remain an open question, but experiments point to adsorbates on trap electrodes as one likely source. Many different models of anomalous heating have been proposed, but these models have yet to pinpoint the atomistic origin of the experimentally-observed 1/ω electric field noise scaling seen in ion traps at frequencies between 0.1-10 MHz. In this work, we show that a model based on previously-proposed surface-induced dipole fluctuations on adsorbates, but which also incorporates interparticle interaction dynamics through molecular dynamics simulations of up to multiple monolayers of adsorbates, gives rise to 1/ω frequency scaling at the MHz frequencies typically employed in ion traps. These results demonstrate that moderate-to-high densities of adsorbates can give rise to a set of activated motions that produce the 1/ω noise observed in ion traps and that collective adsorbate motions produce the observed noise spectra that a non-interacting model does not capture.

Advances in molecular computing have been thwarted by the lack of theoretical underpinnings that are both generalizable and experimentally practical. In a recent issue of iScience, Dueñ as-Díez and Pé rez-Mercader begin to fill this void by illustrating the correspondence between Chomsky's hierarchy of formal grammars and example chemical automata.