Cryptanalysis of a multi-party quantum key agreement protocol with single particles

Recently, Sun et al. [Quant Inf Proc DOI: 10.1007/s11128-013-0569-x] presented an efficient multi-party quantum key agreement (QKA) protocol by employing single particles and unitary operations. The aim of this protocol is to fairly and securely negotiate a secret session key among $N$ parties with a high qubit efficiency. In addition, the authors claimed that no participant can learn anything more than his/her prescribed output in this protocol, i.e., the sub-secret keys of the participants can be kept secret during the protocol. However, here we points out that the sub-secret of a participant in Sun et al.'s protocol can be eavesdropped by the two participants next to him/her. In addition, a certain number of dishonest participants can fully determine the final shared key in this protocol. Finally, we discuss the factors that should be considered when designing a really fair and secure QKA protocol.Comment: 7 page

Integrable Open Spin Chains from Flavored ABJM Theory

We compute the two-loop anomalous dimension matrix in the scalar sector of planar ${\cal N}=3$ flavored ABJM theory. Using coordinate Bethe ansatz, we obtain the reflection matrix and confirm that the boundary Yang-Baxter equations are satisfied. This establishes the integrability of this theory in the scalar sector at the two-loop order.Comment: v2, 25 pages, 2 figures, minor corrections, references adde

MTML-msBayes: Approximate Bayesian comparative phylogeographic inference from multiple taxa and multiple loci with rate heterogeneity

<p>Abstract</p> <p>Background</p> <p>MTML-msBayes uses hierarchical approximate Bayesian computation (HABC) under a coalescent model to infer temporal patterns of divergence and gene flow across codistributed taxon-pairs. Under a model of multiple codistributed taxa that diverge into taxon-pairs with subsequent gene flow or isolation, one can estimate hyper-parameters that quantify the mean and variability in divergence times or test models of migration and isolation. The software uses multi-locus DNA sequence data collected from multiple taxon-pairs and allows variation across taxa in demographic parameters as well as heterogeneity in DNA mutation rates across loci. The method also allows a flexible sampling scheme: different numbers of loci of varying length can be sampled from different taxon-pairs.</p> <p>Results</p> <p>Simulation tests reveal increasing power with increasing numbers of loci when attempting to distinguish temporal congruence from incongruence in divergence times across taxon-pairs. These results are robust to DNA mutation rate heterogeneity. Estimating mean divergence times and testing simultaneous divergence was less accurate with migration, but improved if one specified the correct migration model. Simulation validation tests demonstrated that one can detect the correct migration or isolation model with high probability, and that this HABC model testing procedure was greatly improved by incorporating a summary statistic originally developed for this task (Wakeley's <it>Ψ_W</it>). The method is applied to an empirical data set of three Australian avian taxon-pairs and a result of simultaneous divergence with some subsequent gene flow is inferred.</p> <p>Conclusions</p> <p>To retain flexibility and compatibility with existing bioinformatics tools, MTML-msBayes is a pipeline software package consisting of Perl, C and R programs that are executed via the command line. Source code and binaries are available for download at <url>http://msbayes.sourceforge.net/</url> under an open source license (GNU Public License).</p

Association Between Acculturation and Body Weight Status Among Migrant Children in Guangzhou, China: A Cross-Sectional Study

Objective To assess the association between acculturation and body weight status among internal migrant children in China. Design, setting and participants A cross-sectional study was conducted among 1154 pairs of migrant children aged 11–17 years and their primary caregivers in Guangzhou, China, from April to May 2016. Measures Migrant children’s body weight status was measured by body mass index. Acculturation was measured by a questionnaire, developed and validated by the research team. The questionnaire had three dimensions with five factors, namely language, social interaction, custom, dressing and diet. Social anxiety was measured by Social Anxiety Scale for Children. Food intake was measured by the food frequency table that was developed from a previous study. Logistic regression was performed to examine the association between acculturation and overweight/obesity while controlling for migrant children’s and their caregivers’ demographic characteristics, children’s social anxiety and food intake. Results Seventy-six out of 1154 (6.6%) migrant children were overweight, and 36 (3.1%) were obese. The overall prevalence of overweight/obesity was 12.5% in boys, and 6.1% in girls (pConclusions The low levels of acculturation was associated with overweight/obesity among migrant children in Guangzhou, China. Promoting healthy acculturation and social campaign on healthy body weight may help prevent childhood overweight/obesity. Young migrant children, boys and children living with urban-to urban migrant caregivers should be the target subgroups

A Holographic Theory for the Phase Transitions Between Fermionic Symmetry-protected Topological States

In an earlier work we developed a holographic theory for the phase transition between bosonic symmetry-protected topological (SPT) states. This paper is a continuation of it. Here we present the holographic theory for fermionic SPT phase transitions. We show that in any dimension $d$, the critical states of fermionic SPT phase transitions has an emergent $Z_2^T$ symmetry and can be realized on the boundary of a $d+1$-dimensional bulk SPT with an extra $Z_2^T$ symmetry.Comment: 35 pages, 10 figure