Speaker
Description
We readdress quantum criticality of itinerant Fermi systems in dimensionality d=2 adopting the Wetterich equation as the starting point. Upon neglecting Fermi self-energy in the loop integrals of the functional RG flow, we identify a non-Fermi liquid RG fixed point and recover the features of earlier RPA-type approaches in the entire frequency range. In a subsequent step, focusing on the low-energy regime, we self-consistently include scaling of the self-energy and the Yukawa coupling. We find a generic instability of the non-Fermi liquid RG fixed point. This implies, at least at this truncation level, absence of the QCP with ordering wavevector $\vec{Q}=0$ and development of a first-order phase transition or a phase characterized by $\vec{Q}\neq 0$.
| Affiliation | Institute of Theoretical Physics, Faculty of Physics, University of Warsaw |
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| Career status | Senior |