N=18 ; Nc = 36
ISOSTATIC É
just enough contacts Nc to fix all N particles
i.e. 2N contacts (in 2 dimensions)
not quite
jammed: remove 1 contact
Éliberates 1 FREE MODEÉe g
Free modes
are É extended (like acoustic modes), heterogeneous (unlike acoustic).
Can
0-frequency free modes explain low-frequency modes of jammed system?
D. Head (2003)
L. Silbert (2005)
Nearly
isostatic packings have free modes