TY - JOUR
T1 - Evidence for marginal stability in emulsions
AU - Lin, Jie
AU - Jorjadze, Ivane
AU - Pontani, Lea Laetitia
AU - Wyart, Matthieu
AU - Brujic, Jasna
N1 - Publisher Copyright:
© 2016 American Physical Society.
PY - 2016/11/8
Y1 - 2016/11/8
N2 - We report the first measurements of the effect of pressure on vibrational modes in emulsions, which serve as a model for soft frictionless spheres at zero temperature. As a function of the applied pressure, we find that the density of states D(ω) exhibits a low-frequency cutoff ω∗, which scales linearly with the number of extra contacts per particle δz. Moreover, for ω<ω∗, our results are consistent with D(ω)∼ω2/ω∗2, a quadratic behavior whose prefactor is larger than what is expected from Debye theory. This surprising result agrees with recent theoretical findings [E. DeGiuli, A. Laversanne-Finot, G. A. Düring, E. Lerner, and M. Wyart, Soft Matter 10, 5628 (2014); S. Franz, G. Parisi, P. Urbani, and F. Zamponi, Proc. Natl. Acad. Sci. U.S.A. 112, 14539 (2015)]. Finally, the degree of localization of the softest low frequency modes increases with compression, as shown by the participation ratio as well as their spatial configurations. Overall, our observations show that emulsions are marginally stable and display non-plane-wave modes up to vanishing frequencies.
AB - We report the first measurements of the effect of pressure on vibrational modes in emulsions, which serve as a model for soft frictionless spheres at zero temperature. As a function of the applied pressure, we find that the density of states D(ω) exhibits a low-frequency cutoff ω∗, which scales linearly with the number of extra contacts per particle δz. Moreover, for ω<ω∗, our results are consistent with D(ω)∼ω2/ω∗2, a quadratic behavior whose prefactor is larger than what is expected from Debye theory. This surprising result agrees with recent theoretical findings [E. DeGiuli, A. Laversanne-Finot, G. A. Düring, E. Lerner, and M. Wyart, Soft Matter 10, 5628 (2014); S. Franz, G. Parisi, P. Urbani, and F. Zamponi, Proc. Natl. Acad. Sci. U.S.A. 112, 14539 (2015)]. Finally, the degree of localization of the softest low frequency modes increases with compression, as shown by the participation ratio as well as their spatial configurations. Overall, our observations show that emulsions are marginally stable and display non-plane-wave modes up to vanishing frequencies.
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U2 - 10.1103/PhysRevLett.117.208001
DO - 10.1103/PhysRevLett.117.208001
M3 - Article
AN - SCOPUS:84994910610
SN - 0031-9007
VL - 117
JO - Physical Review Letters
JF - Physical Review Letters
IS - 20
M1 - 208001
ER -