New R-matrices from representations of braid-monoid algebras based on superalgebras

In this paper we discuss representations of the Birman–Wenzl–Murakami algebra as well as of its dilute extension containing several free parameters. These representations are based on superalgebras and their baxterizations permit us to derive novel trigonometric solutions of the graded Yang–Baxter equation. In this way we obtain the multiparametric R-matrices associated to the $U_q[\mathit{sl}{(r|2m)}^{(2)}]$, $U_q[\mathit{osp}{(r|2m)}^{(1)}]$ and $U_q[\mathit{osp}{(r=2n|2m)}^{(2)}]$ quantum symmetries. Two other families of multiparametric R-matrices not predicted before within the context of quantum superalgebras are also presented. The latter systems are indeed non-trivial generalizations of the $U_q[D_{n+1}^{(2)}]$ vertex model when both distinct edge variables statistics and extra free-parameters are admissible.     

A fresh look into m¯c,b(m¯c,b) and precise fD(s),B(s) from heavy–light QCD spectral sum rules

Using recent values of the QCD (non-)perturbative parameters given in Table 1 and an estimate of the N3LO QCD perturbative contributions based on the geometric growth of the PT series, we re-use QCD spectral sum rules (QSSR) known to N2LO PT series and including all dimension-six NP condensate contributions in the full QCD theory, for improving the existing estimates of ${\overline{m}}_{c,b}$ and $f_{D_{(s)},B_{(s)}}$ from the open charm and beauty systems. We especially study the effects of the subtraction point on “different QSSR data” and use (for the first time) the Renormalization Group Invariant (RGI) scale-independent quark masses in the analysis. The estimates [rigourous model-independent upper bounds within the SVZ framework] reported in Table 8: $f_D/f_{\pi }=1.56(5)$ $[?1.68(1)]$, $f_B/f_{\pi }=1.58(5)$ $[?1.80(3)]$ and $f_{D_s}/f_K=1.58(4)$ $[?1.63(1)]$, $f_{B_s}/f_K=1.50(3)$ $[?1.61(3.5)]$, which improve previous QSSR estimates, are in perfect agreement (in values and precisions) with some of the experimental data on $f_{D,D_s}$ and on recent lattice simulations within dynamical quarks. These remarkable agreements confirm both the success of the QSSR semi-approximate approach based on the OPE in terms of the quark and gluon condensates and of the Minimal Duality Ansatz (MDA) for parametrizing the hadronic spectral function which we have tested from the complete data of the $J/\psi$ and ? systems. The values of the running quark masses ${\overline{m}}_c(m_c)=1286(66)\text{MeV}$ and ${\overline{m}}_b(m_b)=4236(69)\text{MeV}$ from $M_{D,B}$ are in good agreement though less accurate than the ones from recent $J/\psi$ and ? sum rules.     

Disorder dependence electron phonon scattering rate of V82Pd18 − xFex alloys at low temperature

We have systematically investigated the disorder dependence electron phonon scattering rate in three dimensional disordered V₈₂Pd_18 ? xFe_x alloys. A minimum in temperature dependence resistivity curve has been observed at low temperature $T=T_{\mathrm{m}}$. In the temperature range $5\text{ K}\le T\le T_{\mathrm{m}}$ the resistivity correction follows ${{\rho }_{\mathrm{o}}}^{5/2}{T}^{1/2}$ law. The dephasing scattering time has been calculated from analysis of magnetoresistivity by weak localization theory. The electron dephasing time is dominated by electron–phonon scattering and follows anomalous temperature (T) and disorder $({\rho }_0)$ dependence behaviour like ${\tau }_{\mathrm{e}\text{-}\mathrm{ph}}^{?1}\propto T^2/{\rho }_0$, where ${\rho }_0$ is the impurity resistivity. The magnitude of the saturated dephasing scattering time $({\tau }_0)$ at zero temperature decreases with increasing disorder of the samples. Such anomalous behaviour of dephasing scattering rate is still unresolved.     

The first principle study of the electronic structure of SixGe(1−x) alloy films

First principles calculation based on density functional theory (DFT) with the generalized gradient approximation (GGA) are carried out to investigate the electronic band structures of ${\text{Si}}_x{\text{Ge}}_{(1?x)}$ alloys nanofilms. The calculation results show that the band gaps of (100), (110) and (111) surfaces ${\text{Si}}_x{\text{Ge}}_{(1?x)}$ alloy films with different thickness first increase with the increase of Si content, then flatten out, and finally decrease. At the same time, the transformation of direct band gap and indirect band gap occurs when the thickness of films and Si content of the three surface ${\text{Si}}_x{\text{Ge}}_{(1?x)}$ alloy films changes to a certain critical condition. It will be a good way to obtain direct-gap band emission in ${\text{Si}}_x{\text{Ge}}_{(1?x)}$ alloys materials.