Figure 2:
Modes from numerical diagonalization. Complex amplitudes 
and 
are shown as open arrows ( ---
) and closed arrows (
---
), respectively. (a) Local mode, with 
arrows enlarged by a factor of 4. (b) Nonlocal
m=0 mode, with 
arrows enlarged
by a factor of 8. (c) 
translational mode, with equal
scales for 
and 
arrows.