# Comparison of the $\pi$ and $\Delta$ operator approximations for the two-dimensional t-J model

Authors
Type
Preprint
Publication Date
Jul 28, 1999
Submission Date
Jul 28, 1999
Identifiers
DOI: 10.1016/S0375-9601(99)00658-1
arXiv ID: cond-mat/9907437
Source
arXiv
We compare the spectra of the new $\pi$ operator of the SO(5) theory and the conventional $\Delta$ operator for the two-dimensional t-J model. We also calculate the weight transferred to the two-hole ground state from half-filling by these operators. We find that the spectra of these operators are quite similar and the weight for the $\pi$ operator is smaller than the weight for the $\Delta$ operator. We argue that the two-dimensional t-J model does not have a good approximate SO(5) symmetry claimed in Ref. 1.