On a Problem of Ruderman

Ruderman-Kittel-Kasuya-Yosida interactions on a bipartite lattice

Carrier-mediated exchange coupling, known as Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction, plays a fundamental role in itinerant ferromagnetism and has great application potentials in spintronics. A recent theorem based on the imaginary-time method shows that the oscillatory RKKY interaction becomes commensurate on bipartite lattice and predicts that the effective exchange coupling is alway...

Spin-Lattice Order in One-Dimensional Conductors: Beyond the RKKY Effect.

We investigate magnetic order in a lattice of classical spins coupled to an isotropic gas of one-dimensional conduction electrons via local exchange interactions. The frequently discussed Ruderman-Kittel-Kasuya-Yosida effective exchange model for this system predicts that spiral order is always preferred. Here we consider the problem nonperturbatively, and find that such order vanishes above a ...

Chiral corrections to the Kroll–Ruderman theorem

We calculate the one–loop corrections to the Kroll–Ruderman low–energy theorems for charged pion photoproduction in the framework of heavy baryon chiral perturbation theory. We predict the threshold S–wave multipole E0+ to be E thr 0+ (γp → π+n) = (28.2 ± 0.6) · 10/Mπ and Ethr 0+ (γn → π−p) = (−32.7 ± 0.6) · 10/Mπ, respectively, for a fixed pion–nucleon coupling constant, gπN = 13.4. A comparis...

The Realities of Management Promotion Center for Creative Leadership

Atmospheric Radiation Measurement Program (ARM) - Summer 1995 Review