| Copyright © 2011, R. Hilfer, Stuttgart | Content is made available under Creative Commons Attribution-NonCommercial-NoDerivs (CC BY-NC-ND) License; additional terms may apply. |  |
This article is dedicated to V. Spicka and Th. Nieuwenhuizen. The author thanks R. Balian and V. Spicka for discussions and encouragement.
| Copyright © 2011, R. Hilfer, Stuttgart | Content is made available under Creative Commons Attribution-NonCommercial-NoDerivs (CC BY-NC-ND) License; additional terms may apply. | |