Ghost spins and novel quantum critical behavior in a spin chain with local bond-deformation

Abstract

We study the boundary impurity-induced critical behavior in an integrable SU(2)-invariant model consisting of an open Heisenberg chain of arbitrary spin-$S$ (Takhatajian-Babujian model) interacting with an impurity of spin $\overrightarrow{S^{\prime }}$ located at one of the boundaries. For $S=1/2$ or $S^{\prime }=1/2$, the impurity interaction has a very simple form $J{\vec{S}}_1\cdot \overrightarrow{S^{\prime }}$ which describes the deformed boundary bond between the impurity $\overrightarrow{S^{\prime }}$ and the first bulk spin ${\vec{S}}_1$ with an arbitrary strength $J$. With a weak coupling $0<J<J_0/[(S+S^{\prime }{)}^2-1/4]$, the impurity is completely compensated, undercompensated, and overcompensated for $S=S^{\prime }$, $S>S^{\prime }$ and $S<S^{\prime }$ as in the usual Kondo problem. While for strong coupling $J\ge J_0/[(S+S^{\prime }{)}^2-1/4]$, the impurity spin is split into two ghost spins. Their cooperative effect leads to a variety of new critical behaviors with different values of $|S^{\prime }-S|$.

16 pages revtex, no figure

References in corpus (15)

• Distribution of Eigenvalues in Non-Hermitian Anderson Model
• Winding Numbers, Complex Currents, and Non-Hermitian Localization
• Kondo Effect in a Luttinger Liquid: Exact Results from Conformal Field Theory
• Fermi and Non-Fermi behavior in the anisotropic Multichannel Kondo Model -- Bethe Ansatz solution
• Surface excitations and surface energy of the antiferromagnetic XXZ chain by the Bethe ansatz approach
• Boundary bound states and boundary bootstrap in the sine-Gordon model with Dirichlet boundary conditions.
• Exact Results for a Kondo Problem in One Dimensional t-J Model
• Integrable impurity in the supersymmetric t-J model
• Impurity in a Luttinger liquid away from half-filling: a numerical study
• Exact Boundary Critical Exponents and Tunneling Effect in Integrable Models for Quantum Wires
• Spectrum of boundary states in the open Hubbard chain
• Anisotropic Spin-1/2 Heisenberg Chain with Open Boundary Conditions
• Universal cross-over behavior of a magnetic impurity and consequences for doping in spin-1/2 chains
• Scalar potential effect in an integrable Kondo model
• A two-channel Kondo impurity in the spin-1/2 chain: Consequences for Knight shift experiments

Cited by in corpus (6)

• Exact solution of the spin-s Heisenberg chain with generic non-diagonal boundaries
• Phase diagram of an impurity in the spin-1/2 chain: two channel Kondo effect versus Curie law
• Open su(4)-invariant spin ladder with boundary defects
• Logarithmic corrections from ferromagnetic impurity ending bonds of open antiferromagnetic host chains
• Coqblin-Schrieffer impurity in a singular metal
• Absence of overscreened Kondo effect in ferromagnetic host