Issue
EPL
Volume 86, Number 6, June 2009
Article Number 67012
Number of page(s) 6
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/86/67012
Published online 10 July 2009
EPL, 86 (2009) 67012
DOI: 10.1209/0295-5075/86/67012

Interacting resonant level coupled to a Luttinger liquid: Universality of thermodynamic properties

M. Goldstein, Y. Weiss and R. Berkovits

The Minerva Center, Department of Physics, Bar-Ilan University - Ramat-Gan 52900, Israel

goldshm@mail.biu.ac.il

received 2 April 2009; accepted in final form 3 June 2009; published June 2009
published online 10 July 2009

Abstract
We investigate a model of a single resonant level coupled to the edge of a quantum wire in the Luttinger-liquid phase or to the middle of a chiral Luttinger liquid via both tunneling and a contact interaction. Utilizing the Yuval-Anderson approach, we map this model onto a classical 1D Coulomb gas in which all the details of both the interactions in the lead and the level-lead interaction enter only through the corresponding Fermi-edge singularity exponent, which we explicitly evaluate using the Bethe ansatz solution for a particular model of the lead. Thus the population, dynamical capacitance and level entropy are universal in the sense of being equal for models with interactions differing in magnitude and even in sign. We demonstrate this to hold quantitatively using density matrix renormalization group calculations. Since the Coulomb gas description is of the single-channel Kondo type, we infer that the universality we found implies that Luttinger-liquid physics has no qualitative effect on these properties, in contrast with perturbative results.

PACS
73.21.La - Quantum dots.
73.21.Hb - Quantum wires.
71.10.Pm - Fermions in reduced dimensions (anyons, composite fermions, Luttinger liquid, etc.).

© EPLA 2009