Critical Exponent Induced by Impurity Effect

Impurity induced spin texture in quantum critical 2D antiferromagnets.

We describe the uniform and staggered magnetization distributions around a vacancy in a quantum critical two-dimensional S=1/2 antiferromagnet. The distributions are delocalized across the entire sample with a universal functional form arising from an uncompensated Berry phase. The numerical results, obtained using quantum Monte Carlo simulations of the Heisenberg model on bilayer lattices with...

Elliptic Equations with Critical Exponent

where As3 is the Laplace-Beltrami operator on B' . Let 0* C (0, 7r) be the radius o r B ' , i.e., the geodesic distance of the North pole to OBq The values 0 < 0* < 7r/2 correspond to a spherical cap contained in the Northern hemisphere, 0* -7r/2 corresponds to B ~ being the Northern hemisphere and the values rr/2 < 0* < ~c correspond to a spherical cap which covers the Northern hemisphere. Fin...

Scrutiny of the Critical Exponent Paradigm, as Exemplified by Gelation

The conflict between classical and modern theories of criticality is resolved by recognising that both theories work with approximate models, whose relative merits can be assessed by their response to efforts to refine them. Contrary to many claims, critical exponents are not tools fitted to discriminate between different models. True, Riemannian theory which characterises analytic functions in...

Dynamics of a tunneling magnetic impurity: Kondo effect induced incoherence.

We study how the formation of the Kondo compensation cloud influences the dynamical properties of a magnetic impurity that tunnels between two positions in a metal. The Kondo effect dynamically generates a strong tunneling impurity-conduction electron coupling, changes the temperature dependence of the tunneling rate, and may ultimately result in the destruction of the coherent motion of the pa...

Impurity Induced States