Manumitting slave-spins in the Anderson impurity model

Abstract

We show that a generic single-orbital Anderson impurity model, lacking for instance any kind of particle-hole symmetry, can be exactly mapped without any constraint onto a resonant level model coupled to two Ising variables, which reduce to one if the hybridisation is particle-hole symmetric. The mean-field solution of this model is found to be stable to unphysical spontaneous magnetisation of the impurity, unlike the saddle-point solution in the standard slave-boson representation. Remarkably, the mean-field estimate of the Wilson ratio approaches the exact value $R_{\text{W}}=2$ in the Kondo regime.

References in corpus (4)

• Orbital selective Mott transition in multi-band systems: slave-spin representation and dynamical mean-field theory
• Full counting statistics for the Kondo dot in the unitary limit
• Dynamically Generated Double Occupancy as a Probe of Cold Atom Systems
• Analytical slave-spin mean-field approach to orbital selective Mott insulators

Cited by in corpus (2)

• Transport through a magnetic impurity: a slave-spin approach
• Slave-spin approach to the Anderson-Josephson quantum dot