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While the problem of calculating critical exponents was believed to be essentially solved by some experts already in the 1980s, this does not hold true for metallic systems at present. In a recent study of the spin-fermion model [1], Sur and Lee have found the first renormalization group fixed point for a quantum-critical metal using an epsilon-expansion around $d=3$. The critical theory was shown to have a quasi-local boson and one-dimensional electrons. However, the nature of potential fixed points in the physical dimensionality $d=2$ and the values of critical exponents are an important open problem. In this talk, I will therefore present first attempts to tackle this problem within a Wilsonian-type renormalization group framework, where modes with decreasing momenta are integrated out successively. [1] Sur and Lee, PRB 91, 125136 (2015)

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Stefan Maier, University of Cologne
Seminar Room 0.03, ETP
Contact: not specified