Lambda and Anti-Lambda Hypernuclei in Relativistic Mean-field Theory

Several aspects about $\Lambda$-hypernuclei in the relativistic mean field theory, including the effective $\Lambda$-nucleon coupling strengths based on the successful effective nucleon-nucleon interaction PK1, hypernuclear magnetic moment and $\bar\Lambda$-hypernuclei, have been presented. The effect of tensor coupling in $\Lambda$-hypernuclei and the impurity effect of $\bar\Lambda$ 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

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

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>_e) 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>_e 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>_e) both inside and outside the growing season. There was no significant change in CO₂ emissions under N application. <i>R</i>_e outside the growing season was at least equivalent to 9.4% of the CO₂ fluxes during the growing season (GS). Annual <i>R</i>_e was calculated to be 279.0–403.9 g CO₂ m⁻² yr⁻¹ in Bayinbuluk alpine grasslands. In addition, our results indicate that soil temperature was the dominant abiotic factor regulating variation in <i>R</i>_e in the cold and arid environment. Our results suggest that short-term N additions exert no significant effect on CO₂ emissions in alpine grassland