Transmission phase shifts of Kondo impurities

Abstract

We study the coherent properties of transmission through Kondo impurities, by considering an open Aharonov-Bohm ring with an embedded quantum dot. We develop a novel many-body scattering theory which enables us to calculate the conductance through the dot, the transmission phase shift, and the normalized visibility, in terms of the single-particle T-matrix. For the single-channel Kondo effect, we find at temperatures much below the Kondo temperature $T_K$ that the transmission phase shift is π/2 without any corrections up to order (T/T_K)^2. The visibility has the form 1-(πT/T_K)^2. For the non-Fermi liquid fixed point of the two channel Kondo, we find that transmission phase shift is π/2 despite the fact that a scattering phase shift is not defined. At zero temperature the visibility is 1/2, thus at zero temperature exactly half of the conductance is carried by single-particle processes. We explain that the spin summation masks the inherent scattering phases of the dot, which can be accessed only via a spin-resolved experiment. In addition, we calculate the effect of magnetic field and channel anisotropy, and generalize to the k-channel Kondo case.

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Cited by in corpus (5)

• Hierarchical entanglement shells of multichannel Kondo clouds
• SO(5) critical point in a spin-flavor Kondo device -- Bosonization and refermionization solution
• Conductance of closed and open long Aharonov-Bohm-Kondo rings
• Probing single-electron scattering through a non-Fermi liquid charge-Kondo device
• Transmission phase evolution in fully screened and overscreened Kondo impurities