(g-2) from Lattice

Anomalous magnetic moment of the muon, a_mu=(g-2)_mu/2, is one of the most
precisely measured quantities in particle physics and it provides a
stringent test of the standard model. With the planned improvement of the
experimental precision at Fermilab and at J-PARC further reduction of the
theoretical uncertainty is required, in order to be able to resolve the
current discrepancy between the experimental measurement of a_mu and its
theoretical prediction, and potentially gain insight into new physics. The
dominant source of the uncertainty in the theoretical prediction of a_mu are
the errors of the hadronic contributions. In this talk I will explain
several promising approaches for a precise determination of the leading
hadronic contribution to a_mu. Finally, I will discuss the relevance of a
precise estimate of the size of the isospin breaking effects for obtaining
this quantity from lattice QCD simulations with sub-percent precision.