We present the quantum critical theory of an interacting nodal Fermi liquid of quasirelativistic pseudospin-$3/2$ fermions that have a noninteracting birefringent spectrum with two distinct Fermi velocities. When such quasiparticles interact with gapless bosonic degrees of freedom that mediate either the long-range Coulomb interaction or its short range component (responsible for spontaneous symmetry breaking), in the deep infrared or quantum critical regime in two dimensions, the system is, respectively, described by a marginal- or a non-Fermi liquid of relativistic spin-$1/2$ fermions (possessing a unique velocity), and is always a marginal Fermi liquid in three dimensions. We consider a possible generalization of these scenarios to fermions with an arbitrary half-odd-integer spin, and conjecture that critical spin-$1/2$ excitations represent a superuniversal description of the entire family of interacting quasirelativistic fermions.

• Received 10 April 2018
• Revised 6 June 2018

DOI:https://doi.org/10.1103/PhysRevLett.121.157602