  One of the greatest challenges to Landau's Fermi liquid theory - the standard
theory of metals - is presented by complex materials with strong electronic
correlations. In these materials, non-Fermi liquid transport and thermodynamic
properties are often explained by the presence of a continuous quantum phase
transition which happens at a quantum critical point (QCP). A QCP can be
revealed by applying pressure, magnetic field, or changing the chemical
composition. In the heavy-fermion compound CeCoIn$_5$, the QCP is assumed to
play a decisive role in defining the microscopic structure of both normal and
superconducting states. However, the question of whether QCP must be present in
the material's phase diagram to induce non-Fermi liquid behavior and trigger
superconductivity remains open. Here we show that the full suppression of the
field-induced QCP in CeCoIn$_5$ by doping with Yb has surprisingly little
impact on both unconventional superconductivity and non-Fermi liquid behavior.
This implies that the non-Fermi liquid metallic behavior could be a new state
of matter in its own right rather then a consequence of the underlying quantum
phase transition.
