Exact Two-Particle Spectrum of the Heisenberg-Peierls Spin Chain

Atsuko Kouzuki, Natsuko Maya, 和子 川崎 +1 more

Hiroaki Onishi, Seiji Miyashita

Andreas Klümper

Julio Abad, Esteve, J. G.

The exact solution for the two particle spectrum of the Heisenberg-Peierls one dimensional spin chain is given by working in the fermionic representation. The resulting equations for the eigenvalues are, in some sense, similar to those of the Richardson's solution of the BCS model and must be solved numerically.

Vladyslav O. Cheranovskii

Dandan Guo, Tom Kennedy, S. Mazumdar

Exact diagonalizations are done to calculate the energy gain from bond alternation in finite spin chains as a function of chain length. Calculations are done for S=1/2, 1, 3/2, and 2. Qualitative differences are found between half-integer and interger spins. Our results (i) indicate the absence of the spin-Peierls transition in systems with integer spins and (ii) suggest a transition in systems with half-integer spins.