Applicability of bosonization and the Anderson-Yuval methods at the strong-coupling limit of quantum impurity problems

作者：Borda L^*; Schiller A; Zawadowski A

来源：Physical Review B, 2008, 78(20): 201301.

DOI：10.1103/PhysRevB.78.201301

The applicability of bosonization and the Anderson-Yuval (AY) approach at strong coupling is investigated by considering two generic impurity models: the interacting resonant-level model and the anisotropic Kondo model. The two methods differ in the renormalization of the conduction-electron density of states (DOS) near the impurity site. Reduction in the DOS, absent in bosonization but accounted for in the AY approach, is shown to be vital in some models yet superfluous in others. The criterion is the stability of the strong-coupling fixed point. Renormalization of the DOS is essential for an unstable fixed point but superfluous when a decoupled entity with local dynamics is formed. This rule can be used to boost the accuracy of both methods at strong coupling.

• 出版日期2008-11