Reply to Comment by E. Babaev and M. Silaev, arXiv:1105.3756

The criticism of Babaev and Silaev notwithstanding, we conclude that our analysis is correct. We have found in our papers on two-band superconductors close to Tc, where the Ginzburg-Landau (GL) theory applies, that these materials are characterized by a single order parameter, governed by a single correlation length. In the GL domain, the order parameters of individual bands are proportional to each other. This happens due to the unavoidable inter-band Josephson coupling. Consequently, in the regime where the GL theory applies, these systems are either type-I or type-II superconductors with no room for so called "1.5-type" superconductivity. This conclusion does not mean that at lower temperatures, outside of the GL domain, the inter-vortex interaction cannot have interesting properties, however, the latter cannot be addressed with the standard GL formalism.Comment: 2 page

Strong coupling theory of heavy fermion criticality

We present a theory of the scaling behavior of the thermodynamic, transport and dynamical properties of a three-dimensional metal at an antiferromagnetic critical point. We show how the critical spin fluctuations at the AFM wavevector q=Q induce energy fluctuations at small q, giving rise to a diverging quasiparticle effective mass over the whole Fermi surface. The coupling of the fermionic and bosonic degrees of freedom leads to a self-consistent relation for the effective mass, which has a strong coupling solution in addition to the well-known weak-coupling, spin-density-wave solution. We thereby use the recently-introduced concept of critical quasiparticles, employing a scale-dependent effective mass ratio m*/m and quasiparticle weight factor Z. As a consequence of the diverging effective mass the Landau Fermi liquid interaction is found to diverge in all channels except the critical one, causing important vertex corrections. The ensuing spin fluctuation spectrum obeys omega/T scaling. Our results are in good agreement with experimental data on the heavy fermion compounds YbRh2Si2$ and CeCu(6-x)Au(x) assuming 3D and 2D spin fluctuations, respectively.Comment: 10 pages, 5 figures, minor errors corrected, new section on scaling, more reference