13,237 research outputs found
Optical properties and Raman scattering of vanadium ladder compounds
We investigate electronic and optical properties of the V-based ladder
compounds NaV2O5, the iso-structural CaV2O5, as well as MgV2O5, which differs
from NaV2O5 and CaV2O5 in the c axis stacking. We calculate ab initio the A_g
phonon modes in these compounds as a basis for the investigation of the
electron-phonon and spin-phonon coupling. The phonon modes together with the
dielectric tensors as a function of the corresponding ion displacements are the
starting point for the calculation of the A_g Raman scattering.Comment: 4 pages, 5 figures, .bbl file with references included. Accepted for
publication in Physica Script
Interference of spin-orbit coupled Bose-Einstein condensates
Interference of atomic Bose-Einstein condensates, observed in free expansion
experiments, is a basic characteristic of their quantum nature. The ability to
produce synthetic spin-orbit coupling in Bose-Einstein condensates has recently
opened a new research field. Here we theoretically describe interference of two
noninteracting spin-orbit coupled Bose-Einstein condensates in an external
synthetic magnetic field. We demonstrate that the spin-orbit and the Zeeman
couplings strongly influence the interference pattern determined by the angle
between the spins of the condensates, as can be seen in time-of-flight
experiments. We show that a quantum backflow, being a subtle feature of the
interference, is, nevertheless, robust against the spin-orbit coupling and
applied synthetic magnetic field.Comment: published versio
Fast and robust spin manipulation in a quantum dot by electric fields
We apply an invariant-based inverse engineering method to control by
time-dependent electric fields electron spin dynamics in a quantum dot with
spin-orbit coupling in a weak magnetic field. The designed electric fields
provide a shortcut to adiabatic processes that flips the spin rapidly, thus
avoiding decoherence effects. This approach, being robust with respect to the
device-dependent noise, can open new possibilities for the spin-based quantum
information processing.Comment: 7 pages, 6 figures, with supplemental material. Errors in the
published version have been correcte
Impact of Flower Harvesting on the Salt Marsh Plant \u3cem\u3eLimonium carolinianum\u3c/em\u3e
Because of the potentially detrimental effects of seed production on adult survivorship and growth, moderate flower harvesting may have little negative impact on population growth of long-lived perennial plants such as Limonium carolinianum (Walter) Britton. We examined this by collecting data on survivorship, growth, and fecundity of an unharvested population over a period of 5 years and conducted a controlled experiment to examine the effect of harvesting on adult survivorship and growth over a 3-year period. Data were summarized in the form of a stage structured matrix population model with a stochastic element that incorporated year-to-year variation in transition probabilities. Contrary to our original hypothesis, we found that preventing seed set through removal of flowers did not increase adult survivorship or growth. By determining the harvest level that reduced population growth rate to 1.0, we estimated the maximum sustainable harvest level to be 16%, a value that is approximately half that of reported harvest levels on accessible marshes in the study area. In spite of this, the reported harvest levels are unlikely to drive local populations to extinction in the foreseeable future. Providing the adult population size is \u3e100 and harvest levels are \u3c90%, time to local extinction will exceed 100 years. This is a function of the very high survivorship of adults in this species and the fact that harvesting has no negative impact on adult survivorship or growth. However, because of the long preadult phase in this species (8–9 years) and the fact that fecundity of young adults is low, recovery from overharvesting is extremely slow. Adult population size can be reduced to 25% of its original value in 7 years at high harvest levels, but it will take 34 years on average to recover once harvesting is terminated
Review of scaled Penning H- surface plasma source with slit emitters for high duty factor linacs
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