Shaking during Ion-Atom Collisions

Shaking (shakeup + shakeoff) probabilities accompanying ion-atom collisions are studied using hydrogenic wavefunctions for K-, L-, M- shell electrons in the sudden approximation limit. The role of recoil velocity in the shaking processes is discussed. Further, it is found that the suddenness of collision between projectile and target nuclei plays a major factor in shaking of respective atomic system than the recoil of nuclei.Comment: 10 page

Near Optimal Subdivision Algorithms for Real Root Isolation

We describe a subroutine that improves the running time of any subdivision algorithm for real root isolation. The subroutine first detects clusters of roots using a result of Ostrowski, and then uses Newton iteration to converge to them. Near a cluster, we switch to subdivision, and proceed recursively. The subroutine has the advantage that it is independent of the predicates used to terminate the subdivision. This gives us an alternative and simpler approach to recent developments of Sagraloff (2012) and Sagraloff-Mehlhorn (2013), assuming exact arithmetic. The subdivision tree size of our algorithm using predicates based on Descartes's rule of signs is bounded by $O(n\log n)$, which is better by $O(n\log L)$ compared to known results. Our analysis differs in two key aspects. First, we use the general technique of continuous amortization from Burr-Krahmer-Yap (2009), and second, we use the geometry of clusters of roots instead of the Davenport-Mahler bound. The analysis naturally extends to other predicates.Comment: 19 pages, 3 figure

Mesoscopic effects in adiabatic spin pumping

We show that temporal shape modulations (pumping) of a quantum dot in the presence of spin-orbital coupling lead to a finite dc spin current. Depending on the strength of the spin-orbit coupling, the spin current is polarized perpendicular to the plane of the two-dimensional electron gas, or has an arbitrary direction subject to mesoscopic fluctuations. We analyze the statistics of the spin and charge currents in the adiabatic limit for the full cross-over from weak to strong spin-orbit coupling.Comment: 4 pages, 1 figure same as version 1. Added a comma to separate the two author name