The Heisenberg antiferromagnet, which arises from the large U Hubbard model, is investigated on the C60 molecule and other fullerenes. The connectivity of C60 leads to an exotic classical ground state with nontrivial topology. We argue that there is no phase transition in the Hubbard model as a function of U/t, and thus the large U solution is relevant for the physical case of intermediate coup...

User-generated passwords tend to be memorable, but not secure. A random, computergenerated 60-bit string is much more secure. However, users cannot memorize random 60bit strings. In this paper, we investigate methods for converting arbitrary bit strings into English word sequences (both prose and poetry), and we study their memorability and other properties.