Theoretical Analysis of the Transmission Phase Shift of a Quantum Dot in the Presence of Kondo Correlations

摘要

In a recent Letter, Jerez, Vitushinsky, and Lavagna (JVL) propose an interpretation of the measurements of the transmission phase shift, δ_(ABI), through a quantum dot (QD) in the Kondo regime, as deduced from placing the QD in a double-slit Aharonov-Bohm interferometer (ABI). Describing the QD (coupled to two reservoirs via one-dimensional leads) by the single level Anderson model (SLAM), JVL argue that the zero magnetic field (H = 0) conductance through the QD is given by G ∝ sin~2(δ_G), with δ_G = δ_(ABI)/2. This Comment questions the validity of this result for the SLAM, since it fails in several exactly known limits. Whether the SLAM describes the experiment is irrelevant to the theoretical problem posed here.