21,330 research outputs found
Nonlinear Sigma Model Analysis of the AFM Phase Transition of the Kondo Lattice
We have studied the antiferromagnetic quantum phase transition of a 2D
Kondo-Heisenberg square lattice using the non-linear sigma model. A
renormalization group analysis of the competing Kondo -- RKKY interaction was
carried out to 1-loop order in the expansion, and a new quantum
critical point is found, dominated by Kondo fluctuations. In addition, the
spin-wave velocity scales logarithmically near the new QCP, i.e breakdown of
hydrodynamic behavior. The results allow us to propose a new phase diagram near
the AFM fixed point of this 2D Kondo lattice model.Comment: 4 pages, 4 figure
A Distributed and Incremental SVD Algorithm for Agglomerative Data Analysis on Large Networks
In this paper, we show that the SVD of a matrix can be constructed
efficiently in a hierarchical approach. Our algorithm is proven to recover the
singular values and left singular vectors if the rank of the input matrix
is known. Further, the hierarchical algorithm can be used to recover the
largest singular values and left singular vectors with bounded error. We also
show that the proposed method is stable with respect to roundoff errors or
corruption of the original matrix entries. Numerical experiments validate the
proposed algorithms and parallel cost analysis
- …