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Cages and anomalous diffusion in vibrated dense granular media
- Source :
- Phys. Rev. Lett. 114, 198001 (2015)
- Publication Year :
- 2015
-
Abstract
- A vertically shaken granular medium hosts a blade rotating around a fixed vertical axis, which acts as a mesorheological probe. At high densities, independently from the shaking intensity, the blade's dynamics show strong caging effects, marked by transient sub-diffusion and a maximum in the velocity power density spectrum (vpds), at a resonant frequency $\sim 10$ Hz. Interpreting the data through a diffusing harmonic cage model allows us to retrieve the elastic constant of the granular medium and its collective diffusion coefficient. For high frequencies $f$, a tail $\sim 1/f$ in the vpds reveals non-trivial correlations in the intra-cage micro-dynamics. At very long times (larger than $10$ s), a super-diffusive behavior emerges, ballistic in the most extreme cases. Consistently, the distribution of slow velocity inversion times $\tau$ displays a power-law decay, likely due to persistent collective fluctuations of the host medium.<br />Comment: 5 pages + 4 page of supplemental material, 6 figures, to be published on Phys. Rev. Lett
- Subjects :
- Condensed Matter - Soft Condensed Matter
Subjects
Details
- Database :
- arXiv
- Journal :
- Phys. Rev. Lett. 114, 198001 (2015)
- Publication Type :
- Report
- Accession number :
- edsarx.1504.07528
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1103/PhysRevLett.114.198001