  We present the prospects of ORCA searches for new physics phenomena using
atmospheric neutrinos. Focus is given to exploiting the impact of strong matter
effects on the oscillation of atmospheric neutrinos in light of expanded
models, such as sterile neutrinos and non-standard interactions. In the
presence of light sterile neutrinos that mix with active neutrinos, additional
resonances and suppressions may occur at different energies. One may also use
neutrino oscillations to probe the properties of the coherent forward
scattering which may be altered by new interactions beyond the Standard Model.
Preliminary studies show that ORCA would be able to probe some parameters of
these models with sensitivity up to one order of magnitude better than current
constraints.
