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We discuss the perturbative control of low-energy effective theory of strongly-interacting systems which cannot be treated within the Landau Fermi liquid framework. These are generically called non-Fermi liquids where quasiparticles do not exist. In particular, we focus on critical Fermi surface states where there is a well-defined Fermi surface, but no quasiparticle resulting from the strong interaction between the Fermi surface and a massless boson. We will show that for Fermi surface having a dimension m>1, the Fermi momentum k_F enters the expressions for physical quantities as a dimensionful parameter leading to UV/IR mixing, thus modifying the naive scaling arguments, whereas for a one-dimensional Fermi surface there is an emergent locality with no such k_F dependence.

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Ipsita Mandal, MPI-PKS Dresden
Seminarraum Altbau Theorie
Contact: Alex Altland