  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 $\nu
=1.02$, spin susceptibility $\gamma = 0.96$, electronic non-Fermi liquid
$\eta^f_\tau = 0.53$, spin-wave Landau damping $\eta^b_\tau = 1.06$), 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.
