One-electron singular branch lines of the Hubbard chain J. M. P. Carmelo, K. Penc, L. M. Martelo, P. D. Sacramento, J. M. B. Lopes dos Santos, R. Claessen, M. Sing and U. Schwingenschlögl Europhys. Lett., 67 2 (2004) 233-239 Published online: 01 July 2004 DOI: 10.1209/epl/i2004-10111-0