Dynamical structure factor of the SU(3) Heisenberg chain: Variational Monte Carlo approach

Article

关键词: ANTIFERROMAGNETIC CORRELATIONS;    HUBBARD-MODEL;    WAVE-FUNCTION;    CONFORMAL-INVARIANCE;    SPIN;    EXCITATIONS;    MAGNETISM;    SYSTEMS;    STATE;    LIMIT;   

DOI  :  10.1103/PhysRevB.104.184426

来源: SCIE

【 摘 要 】

We compute the dynamical spin structure factor S(k, omega) of the SU(3) Heisenberg chain variationally using a truncated Hilbert space spanned by the Gutzwiller projected particle-hole excitations of the Fermi sea, introduced by Dalla Piazza et al. [Nat. Phys. 11, 62 (2015)], with a modified importance sampling. We check the reliability of the method by comparing the S(k, omega) to exact diagonalization results for 18 sites and to the two-soliton continuum of the Bethe ansatz for 72 sites. We get an excellent agreement in both cases. Detailed analysis of the finite-size effects shows that the method captures the critical Wess-Zumino-Witten SU(3)1 behavior and reproduces the correct exponent, with the exception of the size dependence of the weight of the bottom of the conformal tower. We also calculate the single-mode approximation for the SU(N) Heisenberg model and determine the velocity of excitations. Finally, we apply the method to the SU(3) Haldane-Shastry model and find that the variational method gives the exact wave function for the lowest excitation at k = +/- 2 pi /3.

【 授权许可】

Free