Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phonon dispersion curves of two-dimensional colloidal crystals: on the
  wavelength dependence of friction   Digital video-microscopy measurements are reported of both elastic
bandstructures and overdamped phonon decay times in two-dimensional colloidal
crystals. Both quantities together allow to determine the friction coefficients
along various high symmetry directions in q-space. These coefficients contain
valuable information on the hydrodynamic forces acting between the colloidal
particles. We find Stokes-like friction for phonons near the edge of the first
Brillouin zone and vanishing friction coefficients for long wavelength phonons.
The effect of this wavelength dependence in real-space is further investigated
by simulating a crystal with constant friction (Langevin simulation) and
comparing experimentally measured and simulated particle auto-correlation
functions.

12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
1
The categories of this paper are: cs
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex