Search

We present the determination of the charm quark mass, the masses and decay constants of charmed mesons using thirteen 2+1 flavor full-QCD gauge ensembles at five different lattice spacings $a\in[0.05,0.11]$ fm, 8 pion masses $m_{\pi}\in(130,360)$ MeV, and several values of the strange quark mass, which facilitate us to do the chiral and continuum extrapolation. These ensembles are generated through the stout smeared clover fermion action and Symanzik gauge actions with the tadpole improvement. Using QED-subtracted $D_s$ meson mass and non-perturbative renormalization, we predict the charm quark mass in the continuum with physical light and strange quark masses to be {$m_c(m_c)=1.289(17)$} GeV in $\overline{\textrm{MS}}$ scheme, with the systematic uncertainties from lattice spacing determination, renormalization constant, {and fit ansatz} included. Predictions of the open and close charm mesons using this charm quark mass agree with the experimental value at 0.3\% level uncertainty. We obtained {$D_{(s)}$ decay constants and also by far the most precise $D_{(s)}^*$ decay constants $f_{D^*}=0.2321(43)$ GeV and $f_{D^*_s}=0.2743(34)$ GeV}, with the charm quark improved vector current normalization., Comment: 14 pages, 14 figures

Layered transition metal chalcogenides have stimulated a wide research interest due to their many exotic physical properties. In this paper, we studied the magnetotransport properties of the exfoliated TaNiTe5, a recently discovered Dirac nodal-line semimetal. A giant positive magnetoresistance (MR) is observed when the current is parallel to the crystallographic c axis, while it is strongly diminished when the current flows along the a axis. The observed giant MR is gradually suppressed either on reducing the thickness of nanoflake or on increasing temperature. By performing MR measurement in tilted magnetic fields, the interlayer coupling is found to be weakened both by reducing the thickness and by increasing temperature. We propose a mechanism of electron-electron interaction-assisted interlayer transport as a origin of the giant MR. The mechanism is likely to provide a explanation for the giant MR in other layered materials., Comment: 21 pages, 7 figures, 1 table

Highly efficient terahertz (THz) wave sources based on difference frequency generation (DFG) process in nonlinear optical crystals play an important role for the applications of THz wave. In order to find more novel nonlinear crystals, here we theoretically investigate the generation of THz wave using the isomorphs of periodically poled $\mathrm{KTiOPO_4}$ (PPKTP), including periodically poled RTP, KTA, RTA and CTA. By solving the cascaded difference frequency coupled wave equations, it is found that the intensities of the THz wave generated from the cascaded difference frequency processes are improved by 5.27, 2.87, 2.82, 3.03, and 2.76 times from the non-cascaded cases for KTP, RTP, KTA, RTA and CTA, respectively. The effects of the crystal absorption, the phase mismatch and the pump intensity are also analyzed in detail. This study might help to provide a stronger THz radiation source based on the nonlinear crystals., Comment: 9 pages, 5 figures