Quantum Phase Transition and Dynamically Enhanced Symmetry in Quadruple Quantum Dot System
Mesoscale and Nanoscale Physics
2011-09-02 v1 Strongly Correlated Electrons
Abstract
We propose a system of four quantum dots designed to study the competition between three types of interactions: Heisenberg, Kondo and Ising. We find a rich phase diagram containing two sharp features: a quantum phase transition (QPT) between charge-ordered and charge-liquid phases, and a dramatic resonance in the charge liquid visible in the conductance. The QPT is of the Kosterlitz-Thouless type with a discontinuous jump in the conductance at the transition. We connect the resonance phenomenon with the degeneracy of three levels in the isolated quadruple dot and argue that this leads to a Kondo-like dynamical enhancement of symmetry from U(1) x Z_2 to U(1) x U(1).
Cite
@article{arxiv.1008.1262,
title = {Quantum Phase Transition and Dynamically Enhanced Symmetry in Quadruple Quantum Dot System},
author = {Dong E. Liu and Shailesh Chandrasekharan and Harold U. Baranger},
journal= {arXiv preprint arXiv:1008.1262},
year = {2011}
}
Comments
4 pages main text + 4 pages supplementary material