Detection of pairing from the extended Aharonov-Bohm period in strongly correlated electron systems

Inspired by Sutherland's work [Phys. Rev. Lett. 74 (1995) 816] on the detection of bound spin waves, we propose that bound electron states can he detected from the dependence of interacting electron systems on the Aharonov-Bohm flux in the 'extended zone' scheme. where the electron pairing halves the original period of N-alpha flux quanta in a system of linear size N-alpha. Along with the Bethe ansatz analysis, a numerical implementation for keeping track of the adiabatic flow of energy levels is applied to the attractive/repulsive Hubbard model and the t-J ladder.