2015/08/21 by D. P. Barber, Barber, D. P., K. Heinemann +1
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #Accelerator Physics (physics.acc-ph) #Advanced Electron Microscopy Techniques and Applications #FOS: Physical sciences #Magnetic properties of thin films #Quantum and electron transport phenomena
paper · pdf · doi:10.48550/arxiv.1508.05318
openalex publication_date 2015/08/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
This is an addendum to the paper "Some models of spin coherence and decoherence in storage rings" by one of the authors [1] in which spin diffusion in simple electron storage rings is studied. In particular, we illustrate in a compact way, a key implication in the Epilogue of [1], namely that the exact formalism of [1] delivers a rate of depolarisation which can differ from that obtained by the conventional treatments of spin diffusion which rely on the use of the derivative ∂ n/∂η [2,3,4]. As a vehicle we consider a ring with a Siberian Snake and electron polarisation in the plane of the ring (Machine II in [1]). For this simple setup with its one-dimensional spin motion, we avoid having to deal directly with the Bloch equation [5,6] for the polarisation density. Our treatment, which is deliberately pedagogical, shows that the use of ∂ n/∂η provides a very good approximation to the rate of spin depolarisation in the model considered. But it then shows that the exact rate of depolarisation can be obtained by replacing ∂ n/∂η by another derivative as suggested in the Epilogue of [1], while giving a heuristic justification for the new derivative.