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Quantum Phase Transition in a Multi-Level Dot

Walter Hofstetter·Herbert Schoeller
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Abstract

We discuss electronic transport through a lateral quantum dot close to the singlet-triplet degeneracy in the case of a single conduction channel per lead. By applying the Numerical Renormalization Group, we obtain rigorous results for the linear conductance and the density of states. A new quantum phase transition of the Kosterlitz-Thouless type is found, with an exponentially small energy scale $T^*$ close to the degeneracy point. Below $T^*$, the conductance is strongly suppressed, corresponding to a universal dip in the density of states. This explains recent transport measurements.

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Walter Hofstetter, Herbert Schoeller. 2001-12-30. Quantum Phase Transition in a Multi-Level Dot. https://doi.org/10.1103/physrevlett.88.016803

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