The functional renormalization group provides an efficient description of theinterplay and competition of correlations on different energy scales ininteracting Fermi systems. An exact hierarchy of flow equations yields thegradual evolution from a microscopic model Hamiltonian to the effective actionas a function of a continuously decreasing energy cutoff. Practicalimplementations rely on suitable truncations of the hierarchy, which capturenonuniversal properties at higher energy scales in addition to the universallow-energy asymptotics. As a specific example we study transport propertiesthrough a single-level quantum dot coupled to Fermi liquid leads. Inparticular, we focus on the temperature T=0 gate voltage dependence of thelinear conductance. A comparison with exact results shows that the functionalrenormalization group approach captures the broad resonance plateau as well asthe emergence of the Kondo scale. It can be easily extended to more complexsetups of quantum dots.
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