Cluster formation by acoustic forces and active fluctuations in levitated granular matter

Melody X. Lim, Anton Souslov, Vincenzo Vitelli, Heinrich M. Jaeger

Research output: Contribution to journalLetter

1 Citation (Scopus)

Abstract

Mechanically agitated granular matter often serves as a prototype for exploring the rich physics associated with hard-sphere systems, with an effective temperature introduced by vibrating or shaking. While depletion interactions drive clustering and assembly in colloids, no equivalent short-range attractions exist between macroscopic grains. Here we overcome this limitation and investigate granular cluster formation by using acoustic levitation and trapping. Scattered sound establishes short-range attractions between small particles, while detuning the acoustic trap generates active fluctuations. To illuminate the interplay between attractions and fluctuations, we investigate transitions among ground states of two-dimensional clusters composed of a few particles. Our main results, obtained using experiments and modelling, reveal that, in contrast to thermal colloids, in non-equilibrium granular ensembles the magnitude of active fluctuations controls not only the assembly rates but also their assembly pathways and ground-state statistics. These results open up new possibilities for non-invasively manipulating macroscopic particles, tuning their interactions and directing their assembly.
LanguageEnglish
Pages460-464
Number of pages5
JournalNature Physics
Volume15
Issue number5
Early online date4 Mar 2019
DOIs
StatusPublished - 1 May 2019

Cite this

Cluster formation by acoustic forces and active fluctuations in levitated granular matter. / Lim, Melody X.; Souslov, Anton; Vitelli, Vincenzo; Jaeger, Heinrich M.

In: Nature Physics, Vol. 15, No. 5, 01.05.2019, p. 460-464.

Research output: Contribution to journalLetter

Lim, Melody X. ; Souslov, Anton ; Vitelli, Vincenzo ; Jaeger, Heinrich M. / Cluster formation by acoustic forces and active fluctuations in levitated granular matter. In: Nature Physics. 2019 ; Vol. 15, No. 5. pp. 460-464.
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