Loop optimization for tensor network renormalization

We introduce a tensor renormalization group scheme for coarse-graining a two-dimensional tensor network that can be successfully applied to both classical and quantum systems on and off criticality. The key innovation in our scheme is to deform a 2D tensor network into small loops and then optimize the tensors on each loop. In this way, we remove short-range entanglement at each iteration step and significantly improve the accuracy and stability of the renormalization flow. We demonstrate our algorithm in the classical Ising model and a frustrated 2D quantum model.Comment: 15 pages, 11 figures, accepted version for Phys. Rev. Let

Bright 22 μ\mum Excess Candidates from WISE All-Sky Catalog and Hipparcos Main Catalog

In this paper we present a catalog which includes 141 bright candidates ($\leq10.27$ mag, V band) showing the infrared (IR) excess at 22 $\mu$m. Of which, 38 stars are known IR excess stars or disk, 23 stars are double or multiple stars and 4 are Be stars. While the remaining more than 70 stars are identified as the 22 $\mu$m excess candidates in our work. The criterion of selecting candidates is $K_s-[22]_{\mu m}$. All these candidates are selected from \emph{WISE} All-sky data cross-correlated with \emph{Hipparcos} Main Catalog and the likelihood-ratio technique is employed. Considering the effect of background, we introduce the \emph{IRAS} 100 $\mu$m level to exclude the high background. We also estimated the coincidence probability of these sources. In addition, we presented the optical to mid-infrared SEDs and optical images of all the candidates, and gave the observed optical spectra of 6 stars with NAOC's 2.16-m telescope. To measure for the dust amount around each star, the fractional luminosity is also provided. We also test whether our method of selecting IR excess stars can be used to search for extra-solar planets, we cross-matched our catalog with known IR-excess stars having planets but none is matched. Finally, we give the fraction of stars showing IR-excess for different spectral type of main-sequence stars.Comment: 45 pages, 16 figures, 4 tables. Accepted for publication in ApJ

Fidelity susceptibility and long-range correlation in the Kitaev honeycomb model

We study exactly both the ground-state fidelity susceptibility and bond-bond correlation function in the Kitaev honeycomb model. Our results show that the fidelity susceptibility can be used to identify the topological phase transition from a gapped A phase with Abelian anyon excitations to a gapless B phase with non-Abelian anyon excitations. We also find that the bond-bond correlation function decays exponentially in the gapped phase, but algebraically in the gapless phase. For the former case, the correlation length is found to be $1/\xi=2\sinh^{-1}[\sqrt{2J_z -1}/(1-J_z)]$, which diverges around the critical point $J_z=(1/2)^+$.Comment: 7 pages, 6 figure

Reduced expression of Metastasis Suppressor-1 (MTSS1) accelerates progression of human bladder uroepithelium cell carcinoma

Background: Metastasis suppressor 1 (MTSS1) is a multi-functional cytoskeletal protein. Recent research showed that MTSS1 is a potential tumor suppressor in many types of cancer cells, including kidney and bladder cancer cells. However, the clinical implication of MTSS1 in human bladder uroepithelium cell carcinoma (BUCC) and its potential in suppressing BUCC tumorigenesis remains undetermined. In the present study, the expression of MTSS1 in human BUCC tissue samples, and correlations between MTSS1 and pathological grade and stage of the tumors were examined in BUCC specimens. The function of MTSS1 in BUCC progression was explored. Materials and Methods: The mRNA and protein expression of MTSS1 were examined in 68 BUCC tissue samples with matching adjacent normal bladder tissues using quantitative real-time PCR and western blotting. Furthermore, the bladder cancer cell line 5637 was used to determine the anticancer effect of MTSS1. Results: Lower MTSS1 mRNA expression was recorded in BUCC tissues compared to normal bladder tissues. A lower MTSS1 mRNA level was observed in tumors with high clinical stage and with high pathological nuclear grade. Likewise, MTSS1 protein expression in normal bladder tissue was significantly higher than that in BUCC tissue. The protein level of MTSS1 significantly negatively correlated with clinical stage and pathological nuclear grade of BUCC. Cumulative survival curves indicated that MTSS1 expression was negatively correlated with survival time: patients with a high level of MTSS1 had significantly longer survival time than those with a low level of MTSS1 (p<0.001). Overexpression of MTSS1 reduced BUCC cell proliferation, cell-cycle progression and colony formation, but had no influence on BUCC cell apoptosis. Conclusion: Overexpression of MTSS1 suppresses BUCC development, providing a novel perspective for BUCC tumorigenesis and a potential therapeutic target for BUCC

Gene Expression Divergence and Evolutionary Analysis of the Drosomycin Gene Family in Drosophila melanogaster

Drosomycin (Drs) encoding an inducible 44-residue antifungal peptide is clustered with six additional genes, Dro1, Dro2, Dro3, Dro4, Dro5, and Dro6, forming a multigene family on the 3L chromosome arm in Drosophila melanogaster. To get further insight into the regulation of each member of the drosomycin gene family, here we investigated gene expression patterns of this family by either microbe-free injury or microbial challenges using real time RT-PCR. The results indicated that among the seven drosomycin genes, Drs, Dro2, Dro3, Dro4, and Dro5 showed constitutive expressions. Three out of five, Dro2, Dro3, and Dro5, were able to be upregulated by simple injury. Interestingly, Drs is an only gene strongly upregulated when Drosophila was infected with microbes. In contrast to these five genes, Dro1 and Dro6 were not transcribed at all in either noninfected or infected flies. Furthermore, by 5′ rapid amplification of cDNA ends, two transcription start sites were identified in Drs and Dro2, and one in Dro3, Dro4, and Dro5. In addition, NF-κB binding sites were found in promoter regions of Drs, Dro2, Dro3, and Dro5, indicating the importance of NF-κB binding sites for the inducibility of drosomycin genes. Based on the analyses of flanking sequences of each gene in D. melanogaster and phylogenetic relationship of drosomycins in D. melanogaster species-group, we concluded that gene duplications were involved in the formation of the drosomycin gene family. The possible evolutionary fates of drosomycin genes were discussed according to the combining analysis of gene expression pattern, gene structure, and functional divergence of these genes