Quantum criticality and non-Fermi-liquid behavior in a two-level two-lead quantum dot
Abstract
Analytical and continuous-time quantum Monte Carlo methods are used to investigate the possibility of occupation switching and quantum criticality in a model of two quantum impurities coupled to two leads. A general discussion of potential occupancy-switching related quantum critical points is given, and a detailed analysis is made of a specific model which has been recently discussed. For spinless electrons, no phase transition is found. For electrons with spin, a critical value of the interaction strength separates a weak coupling regime in which all properties vary smoothly with parameters from a strong coupling phase in which occupation numbers vary discontinuously as level energies are changed. The discontinuity point is characterized by non-Fermi-liquid behavior. Results for self-energies and correlation functions are given. Phase diagrams are presented.
Cite
@article{arxiv.0909.3120,
title = {Quantum criticality and non-Fermi-liquid behavior in a two-level two-lead quantum dot},
author = {Xin Wang and Andrew J. Millis},
journal= {arXiv preprint arXiv:0909.3120},
year = {2010}
}
Comments
11 pages, 12 figures. To be published on Phys. Rev. B