BETHE-SALPETER EIGENVALUES AND AMPLITUDES FOR THE HALF-FILLED 2-DIMENSIONAL HUBBARD-MODEL

Monte Carlo simulations are used to determine the eigenvalues and eige nfunctions of the particle-hole and particle-particle Bethe-Salpeter e quations for 8 X 8 half-filled Hubbard lattice with U/t = 4 and U/t = 8. In the particle-hole channel, the dominant eigenvalue corresponds t o the Q = (pi,pi) antiferromagnetic correlations. In the particle-part icle channel the amplitude of the leading low-temperature eigenvalue i s an even-frequency d(x2-y2) singlet. Odd-frequency p-wave-singlet and s-wave-triplet amplitudes are also found.