**"Non-Fermi-liquid behavior of large-N**_{B} quantum critical metals"

_{B}quantum critical metals"

A. Liam Fitzpatrick: Shamit Kachru, Jared Kaplan, and S. Raghu; Physical Review B, 04/11/14.

**Abstract**:

The problem of continuous quantum phase transitions in metals involves critical bosons coupled to a Fermi surface. We solve the theory in the limit of a large number, *N**B*, of bosonic flavors, where the bosons transform in the adjoint representation (a matrix representation), while the fermions are in the fundamental representation (a vector representation) of a global *SU*(*N**B*) flavor symmetry group. The leading large *N**B* solution corresponds to a non-Fermi liquid coupled to Wilson-Fisher bosons. In a certain energy range, the fermion velocity vanishes—resulting in the destruction of the Fermi surface. Subleading 1/*N**B* corrections correspond to a qualitatively different form of Landau damping of the bosonic critical fluctuations. We discuss the model in *d*=3−*ε* but because of the additional control afforded by large *N**B*, our results are valid down to *d*=2. In the limit *ε*≪1, the large *N**B* solution is consistent with the renormalization group analysis of Fitzpatrick *et al.* [Phys. Rev. B **88**, 125116 (2013)].