Critical theory of the two-channel Anderson impurity model
Abstract
We construct the boundary conformal field theory that describes the low-temperature behavior of the two-channel Anderson impurity model. The presence of an exactly marginal operator is shown to generate a line of stable fixed points parametrized by the charge valence nc of the impurity. We calculate the exact zero-temperature entropy and impurity thermodynamics along the fixed line. We also derive the critical exponents of the characteristic Fermi edge singularities caused by time-dependent hybridization between conduction electrons and impurity. Our results suggest that in the mixed-valent regime (nc≠0, 1) the electrons participate in two competing processes, leading to frustrated screening of spin and channel degrees of freedom. By combining the boundary conformal field theory with the Bethe-Ansatz solution we obtain a complete description of the low-energy dynamics of the model.
- Publication:
-
Physical Review B
- Pub Date:
- August 2003
- DOI:
- 10.1103/PhysRevB.68.075112
- arXiv:
- arXiv:cond-mat/0301158
- Bibcode:
- 2003PhRvB..68g5112J
- Keywords:
-
- 71.27.+a;
- 75.20.Hr;
- 75.40.-s;
- Strongly correlated electron systems;
- heavy fermions;
- Local moment in compounds and alloys;
- Kondo effect valence fluctuations heavy fermions;
- Critical-point effects specific heats short-range order;
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- Revtex, 19 pages, 3 figures. Replaced with published version (Eq. 25 corrected, minor typographical changes, added references)