10 research outputs found
How to realize a robust practical Majorana chain in a quantum dot-superconductor linear array
Semiconducting nanowires in proximity to superconductors are promising
experimental systems for Majorana fermions, which may ultimately be used as
building blocks for topological quantum computers. A serious challenge in the
experimental realization of the Majorana fermions is the supression of
topological superconductivity by disorder. We show that Majorana fermions
protected by a robust topological gap can occur at the ends of a chain of
quantum dots connected by s-wave superconductors. In the appropriate parameter
regime, we establish that the quantum dot/superconductor system is equivalent
to a 1D Kitaev chain, which can be tuned to be in a robust topological phase
with Majorana end modes even in the case where the quantum dots and
superconductors are both strongly disordered. Such a spin-orbit coupled quantum
dot - s-wave superconductor array provides an ideal experimental platform for
the observation of non-Abelian Majorana modes.Comment: 8 pages; 3 figures; version 2: Supplementary material updated to
include more general proof for localized Majorana fermion
Soil warming accelerates decomposition of fine woody debris
© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Plant and Soil 356 (2012): 405-417, doi:10.1007/s11104-012-1130-x.Soil warming from global climate change could increase decomposition of fine woody debris (FWD), but debris size and quality may mitigate this effect. The goal of this study was to investigate the effect of soil warming on decomposition of fine woody debris of differing size and quality. We placed FWD of two size classes (2 × 20 cm and 4 × 40 cm) and four species (Acer saccharum, Betula lenta, Quercus rubra and Tsuga canadensis) in a soil warming and ambient area at Harvard Forest in central Massachusetts. We collected the debris from each area over two years and measured mass loss and lignin concentration. Warming increased mass loss for all species and size classes (by as much as 30%), but larger debris and debris with higher initial lignin content decomposed slower than smaller debris and debris with lower initial lignin content. Lignin degradation did not follow the same trends as mass loss. Lignin loss from the most lignin-rich species, T. canadensis, was the highest despite the fact that it lost mass the slowest. Our results suggest that soil warming will increase decomposition of FWD in temperate forests. It is imperative that future models and policy efforts account for this potential shift in the carbon storage pool