Galaxy clustering, CMB and supernova data constraints on ϕ\phiCDM model with massive neutrinos

We investigate a scalar field dark energy model (i.e., $\phi$CDM model) with massive neutrinos, where the scalar field possesses an inverse power-law potential, i.e., $V(\phi)\propto {\phi}^{-\alpha}$ ($\alpha>0$). We find that the sum of neutrino masses $\Sigma m_{\nu}$ has significant impacts on the CMB temperature power spectrum and on the matter power spectrum. In addition, the parameter $\alpha$ also has slight impacts on the spectra. A joint sample, including CMB data from Planck 2013 and WMAP9, galaxy clustering data from WiggleZ and BOSS DR11, and JLA compilation of Type Ia supernova observations, is adopted to confine the parameters. Within the context of the $\phi$CDM model under consideration, the joint sample determines the cosmological parameters to high precision. It turns out that $\alpha <4.995$ at 95% CL for the $\phi$CDM model. And yet, the $\Lambda$CDM scenario corresponding to $\alpha = 0$ is not ruled out at 95% CL. Moreover, we get $\Sigma m_{\nu}< 0.262$ eV at 95% CL for the $\phi$CDM model, while the corresponding one for the $\Lambda$CDM model is $\Sigma m_{\nu} < 0.293$ eV. The allowed scale of $\Sigma m_\nu$ in the $\phi$CDM model is a bit smaller than that in the $\Lambda$CDM model. It is consistent with the qualitative analysis, which reveals that the increases of $\alpha$ and $\Sigma m_\nu$ both can result in the suppression of the matter power spectrum. As a consequence, when $\alpha$ is larger, in order to avoid suppressing the matter power spectrum too much, the value of $\Sigma m_\nu$ should be smaller.Comment: 15 pages, 4 figures, 1 tabl

On Longest Repeat Queries Using GPU

Repeat finding in strings has important applications in subfields such as computational biology. The challenge of finding the longest repeats covering particular string positions was recently proposed and solved by \.{I}leri et al., using a total of the optimal $O(n)$ time and space, where $n$ is the string size. However, their solution can only find the \emph{leftmost} longest repeat for each of the $n$ string position. It is also not known how to parallelize their solution. In this paper, we propose a new solution for longest repeat finding, which although is theoretically suboptimal in time but is conceptually simpler and works faster and uses less memory space in practice than the optimal solution. Further, our solution can find \emph{all} longest repeats of every string position, while still maintaining a faster processing speed and less memory space usage. Moreover, our solution is \emph{parallelizable} in the shared memory architecture (SMA), enabling it to take advantage of the modern multi-processor computing platforms such as the general-purpose graphics processing units (GPU). We have implemented both the sequential and parallel versions of our solution. Experiments with both biological and non-biological data show that our sequential and parallel solutions are faster than the optimal solution by a factor of 2--3.5 and 6--14, respectively, and use less memory space.Comment: 14 page

Approaching Gaussian Relay Network Capacity in the High SNR Regime: End-to-End Lattice Codes

We present a natural and low-complexity technique for achieving the capacity of the Gaussian relay network in the high SNR regime. Specifically, we propose the use of end-to-end structured lattice codes with the amplify-and-forward strategy, where the source uses a nested lattice code to encode the messages and the destination decodes the messages by lattice decoding. All intermediate relays simply amplify and forward the received signals over the network to the destination. We show that the end-to-end lattice-coded amplify-and-forward scheme approaches the capacity of the layered Gaussian relay network in the high SNR regime. Next, we extend our scheme to non-layered Gaussian relay networks under the amplify-and-forward scheme, which can be viewed as a Gaussian intersymbol interference (ISI) channel. Compared with other schemes, our approach is significantly simpler and requires only the end-to-end design of the lattice precoding and decoding. It does not require any knowledge of the network topology or the individual channel gains

Production of the superheavy baryon Λccˉ∗(4209)\Lambda _{c\bar{c}}^{\ast}(4209) in kaon-induced reaction

The production of superheavy $\Lambda _{c\bar{c}}^{\ast }(4209)$ baryon in the $K^{-}p\rightarrow \eta _{c}\Lambda$ process via $s$-channel is investigated with an effective Lagrangian approach and the isobar model. Moreover, the $t$-channel with $K^{\ast }$ and $u$-channel with nucleon exchange are also considered, which are regarded as the background for the $\Lambda _{c\bar{c}}^{\ast }(4209)$ production in the $K^{-}p\rightarrow \eta_{c}\Lambda$ reaction. The numerical results indicate it is feasible to searching for the superheavy $\Lambda _{c\bar{c}}^{\ast }(4209)$ via $K^{-}p$ scattering. These theoretical results not only provide valuable informations to future experimental exploration of $\Lambda _{c\bar{c}}^{\ast }(4209)$ resonance but enable us to have a better understanding of the exotic baryons.Comment: 6 page