Non-Standard Neutrino Physics Probed by Tokai-to-Kamioka-Korea Two-Detector Complex

The discovery potentials of non-standard physics (NSP) which might be possessed by neutrinos are examined by taking a concrete setting of Tokai-to-Kamioka-Korea (T2KK) two detector complex which receives neutrino superbeam from J-PARC. We restrict ourselves into \nu_{\mu} and \bar{\nu}_{\mu} disappearance measurement. We describe here only the non-standard interactions (NSI) of neutrinos with matter and the quantum decoherence. It is shown in some favorable cases T2KK can significantly improve the current bounds on NSP. For NSI, for example, epsilon_{\mu\tau} < 0.03, which is a factor 5 severer than the current one.