  We report measurements of magnetic quantum oscillations and specific heat at
low temperatures across a field-induced antiferromagnetic quantum critical
point (QCP)(B_{c0}\approx50T) of the heavy-fermion metal CeRhIn_5. A sharp
magnetic-field induced Fermi surface reconstruction is observed inside the
antiferromagnetic phase. Our results demonstrate multiple classes of QCPs in
the field-pressure phase diagram of this heavy-fermion metal, pointing to a
universal description of QCPs. They also suggest that robust superconductivity
is promoted by unconventional quantum criticality of a fluctuating Fermi
surface.
