Nucleon Structure from Lattice QCD

We report results on the nucleon structure obtained from the lattice quantum chromodynamics calculation. These include the axial, electromagnetic, $\pi NN$, and scalar form factors. The calculation is carried out at $\beta =6$ on a ${16}^3\times 24$ lattice with 24 quenched gauge configurations. The chiral limit results are extrapolated from several light quark cases. For the disconnected insertion (sea-quark contribution), we used the stochastic estimation with the $Z_2$ noise to calculate the diagonal and off-diagonal traces of the inverse matrices with a size of ${10}^6\times {10}^6$. It is found that the $Z_2$ noise is the optimal choice and its comparison with the Gaussian noise for our quark matrix is given. For the sea-quark contribution, we report results on the strange condensate in the nucleon and the $\pi N\sigma$ term.