Non-Fermi liquid behavior near an itinerant quantum critical point
The Hertz-Millis theory describes itinerant quantum phase transitions (e.g. ferromagnetic or antiferromagnetic QCPs in metals). The effective dimension is d+z where z is the dynamical critical exponent (z=2 for AFM, z=3 for FM). Near the QCP (r→0), quantum fluctuations produce a non-Fermi liquid: resistivity ρ∼T^(1+2/z), specific heat C/T∼log(1/T), and the spectral weight is redistributed from sharp quasiparticle peaks to an incoherent background.