3 papers
cond-mat.stat-mech2001
On the Spectrum of the XXZ-chain at roots of unity
D. Braak, N. Andrei
In a recent paper (cond-mat/0009279), Fabricius and McCoy studied the spectrum of the spin 1/2 XXZ-model at Delta = (q+q^{-1})/2 and q^{2N}=1 for integer N >1. They found a certain…
cond-mat.str-el1998
Reply to the Comment on "Bound States in the One-dimensional Hubbard Model"
Daniel Braak, Natan Andrei
We reply to the comment (cond-mat/9806125) by Essler, Goehmann and Korepin, and show that their points are unfounded.
cond-mat.str-el1998
Bound States in the One-dimensional Hubbard Model
D. Braak, N. Andrei
The Bethe Ansatz equations for the one-dimensional Hubbard model are reexamined. A new procedure is introduced to properly include bound states. The corrected equations lead to new…