Universality in antiferromagnetic strange metals

We propose a theory of metals at the spin-density-wave quantum-critical point in spatial dimension d=2. We provide a first estimate of the full set of critical exponents (dynamical exponent z=2.13, correlation length ν=1.02, spin susceptibility γ=0.96, electronic non-Fermi liquid ητf=0.53, spin-wave Landau damping ητb=1.06), which determine the universal power laws in thermodynamics and response functions in the quantum-critical regime relevant for experiments in heavy-fermion systems and iron pnictides. We present approximate numerical and analytical solutions of Polchinski-Wetterich-type flow equations with soft frequency regulators for an effective action of electrons coupled to spin-wave bosons. Performing the renormalization group in frequency instead of momentum space allows to track changes of the Fermi-surface shape and to capture Landau damping during the flow. The technique is easily generalizable from models retaining only patches of the Fermi surface to full, compact Fermi surfaces.