2,253 research outputs found
Lambda and Anti-Lambda Hypernuclei in Relativistic Mean-field Theory
Several aspects about -hypernuclei in the relativistic mean field
theory, including the effective -nucleon coupling strengths based on
the successful effective nucleon-nucleon interaction PK1, hypernuclear magnetic
moment and -hypernuclei, have been presented. The effect of tensor
coupling in -hypernuclei and the impurity effect of to
nuclear structure have been discussed in detail.Comment: 8 pages, 2 figures, Proceedings of the Sendai International Symposium
"Strangeness in Nuclear and Hadronic Systems SENDAI08
Nonorthogonal decoy-state Quantum Key Distribution
In practical quantum key distribution (QKD), weak coherent states as the
photon sources have a limit in secure key rate and transmission distance
because of the existence of multiphoton pulses and heavy loss in transmission
line. Decoy states method and nonorthogonal encoding protocol are two important
weapons to combat these effects. Here, we combine these two methods and propose
a efficient method that can substantially improve the performance of QKD. We
find a 79 km increase in transmission distance over the prior record using
decoy states method.Comment: 4 pages, 1 figure; Revtex4, submitted to PR
f(R) Gravities, Killing Spinor Equations, "BPS" Domain Walls and Cosmology
We derive the condition on f(R) gravities that admit Killing spinor equations
and construct explicit such examples. The Killing spinor equations can be used
to reduce the fourth-order differential equations of motion to the first order
for both the domain wall and FLRW cosmological solutions. We obtain exact "BPS"
domain walls that describe the smooth Randall-Sundrum II, AdS wormholes and the
RG flow from IR to UV. We also obtain exact smooth cosmological solutions that
describe the evolution from an inflationary starting point with a larger
cosmological constant to an ever-expanding universe with a smaller cosmological
constant. In addition, We find exact smooth solutions of pre-big bang models,
bouncing or crunching universes. An important feature is that the scalar
curvature R of all these metrics is varying rather than a constant. Another
intriguing feature is that there are two different f(R) gravities that give
rise to the same "BPS" solution. We also study linearized f(R) gravities in
(A)dS vacua.Comment: 37 pages, discussion on gravity trapping in RSII modified, typos
corrected, further comments and references added; version to appear in JHE
Response of carbon dioxide emissions to sheep grazing and N application in an alpine grassland – Part 2: Effect of N application
Widespread nitrogen (N) enrichment resulting from anthropogenic activities
has led to great changes in carbon exchange between the terrestrial biosphere
and the atmosphere. Grassland is one of the most sensitive ecosystems to N
deposition. However, the effect of N deposition on ecosystem respiration
(<i>R</i><sub>e</sub>) in grasslands has been conducted mainly in temperate
grasslands, which are limited largely by water availability, with few studies
focused on alpine grasslands that are primarily constrained by low
temperatures. Failure to assess the magnitude of the response in
<i>R</i><sub>e</sub> outside the growing season (NGS) in previous studies also
limits our understanding of carbon exchange under N deposition conditions. To
address these knowledge gaps we used a combination of static closed chambers
and gas chromatography in an alpine grassland from 2010 to 2011 to test the
effects of N application on ecosystem respiration (<i>R</i><sub>e</sub>) both
inside and outside the growing season. There was no significant change in
CO<sub>2</sub> emissions under N application. <i>R</i><sub>e</sub> outside the growing
season was at least equivalent to 9.4% of the CO<sub>2</sub> fluxes during the
growing season (GS). Annual <i>R</i><sub>e</sub> was calculated to be
279.0–403.9 g CO<sub>2</sub> m<sup>−2</sup> yr<sup>−1</sup> in Bayinbuluk alpine
grasslands. In addition, our results indicate that soil temperature was the
dominant abiotic factor regulating variation in <i>R</i><sub>e</sub> in the cold and arid
environment. Our results suggest that short-term N additions exert no
significant effect on CO<sub>2</sub> emissions in alpine grassland
Spin and orbital angular momentum in gauge theories (II): QCD and nucleon spin structure
Parallel to the construction of gauge invariant spin and orbital angular
momentum for QED in paper (I) of this series, we present here an analogous but
non-trivial solution for QCD. Explicitly gauge invariant spin and orbital
angular momentum operators of quarks and gluons are obtained. This was
previously thought to be an impossible task, and opens a more promising avenue
towards the understanding of the nucleon spin structure.Comment: 3 pages, no figure; presented by F. Wang at NSTAR200
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