Slave-boson Keldysh field theory for the Kondo effect in quantum dots

Smirnov, Sergey and Grifoni, Milena (2011) Slave-boson Keldysh field theory for the Kondo effect in quantum dots. PHYSICAL REVIEW B, 84 (12): 125303. ISSN 1098-0121,

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Abstract

We present a nonequilibrium nonperturbative field theory for the Kondo effect in strongly interacting quantum dots at finite temperatures. Unifying the slave-boson representation with the Keldysh field integral, an effective Keldysh action is derived and explored in the vicinity of the zero slave-bosonic field configuration. The theory properly reflects the essential features of the Kondo physics and at the same time significantly simplifies a field-theoretic treatment of the phenomenon, avoiding complicated saddle-point analysis or 1/N expansions, used so far. Importantly, our theory admits a closed analytical solution which explains the mechanism of the Kondo effect in terms of an interplay between the real and the imaginary parts of the slave-bosonic self-energy. It thus provides a convenient nonperturbative building block, playing the role of a "free propagator," for more advanced theories. We finally demonstrate that already this simplest possible field theory is able to correctly reproduce experimental data on the Kondo peak observed in the differential conductance, correctly predicts the Kondo temperature, and, within its applicability range, has the same universal temperature dependence of the conductance as the one obtained in numerical renormalization group calculations.

Item Type: Article
Uncontrolled Keywords: SINGLE-ELECTRON TRANSISTOR; DILUTE MAGNETIC-ALLOYS; ANDERSON MODEL; MIXED-VALENCE; EQUILIBRIUM; TRANSPORT; METALS; STATES;
Subjects: 500 Science > 530 Physics
Divisions: Physics > Institute of Theroretical Physics > Chair Professor Grifoni > Group Milena Grifoni
Depositing User: Dr. Gernot Deinzer
Date Deposited: 29 May 2020 13:09
Last Modified: 29 May 2020 13:09
URI: https://pred.uni-regensburg.de/id/eprint/20175

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