title: Quantum Phase Transition and Protected Ideal Transport in a Kondo Chain.
abstract: We study the low energy physics of a Kondo chain where electrons from a one-dimensional band interact with magnetic moments via an anisotropic exchange interaction. It is demonstrated that the anisotropy gives rise to two different phases which are separated by a quantum phase transition. In the phase with easy plane anisotropy, Z_{2} symmetry between sectors with different helicity of the electrons is broken. As a result, localization effects are suppressed and the dc transport acquires (partial) symmetry protection. This effect is similar to the protection of the edge transport in time-reversal invariant topological insulators. The phase with easy axis anisotropy corresponds to the Tomonaga-Luttinger liquid with a pronounced spin-charge separation. The slow charge density wave modes have no protection against localization.
authors.affiliation: Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Tsvelik
authors.affiliation: Ludwig Maximilians University, Arnold Sommerfeld Center and Center for Nano-Science, Munich DE-80333, Germany.
authors.forename: O M
authors.initials: OM
authors.lastname: Yevtushenko