Zhang Gu, Novais E, Baranger Harold U
Department of Physics, Duke University, P.O. Box 90305, Durham, North Carolina 27708, USA.
Centro de Ciíncias Naturais e Humanas, Universidade Federal do ABC, Santo Andrè, São Paulo 09210-580, Brazil.
Phys Rev Lett. 2017 Feb 3;118(5):050402. doi: 10.1103/PhysRevLett.118.050402. Epub 2017 Feb 2.
We show that placing a quantum system in contact with an environment can enhance non-Fermi-liquid correlations, rather than destroy quantum effects, as is typical. The system consists of two quantum dots in series with two leads; the highly resistive leads couple charge flow through the dots to the electromagnetic environment, the source of quantum noise. While the charge transport inhibits a quantum phase transition, the quantum noise reduces charge transport and restores the transition. We find a non-Fermi-liquid intermediate fixed point for all strengths of the noise. For strong noise, it is similar to the intermediate fixed point of the two-impurity Kondo model.
