No abstract

We study isovector unpolarized and helicity parton distribution functions (PDF) of the proton within the framework of large-momentum effective theory. We use a gauge ensemble, generated by the MILC Collaboration, with a superfine lattice spacing of 0.042 fm and a pion mass of 310 MeV, enabling us to simultaneously reach sub-Fermi spatial separations and larger nucleon momenta. We compare the spatial dependence of quasi-PDF matrix elements in different renormalization schemes with the corresponding results of the global fits, obtained using one-loop perturbative matching. We present determinations of the first four moments of the unpolarized and helicity PDFs of proton from the Ioffe-time dependence of the isovector matrix elements, obtained by employing a ratio-based renormalization scheme.

No abstract

No abstract

We present an exploratory lattice QCD investigation of the differences between the valence quark structure of pion and its radial excitation π(1300) in a fixed finite volume using the leading-twist factorization approach. We present evidences that the first pion excitation in our lattice computation is a single particle state that is likely to be the finite volume realization of π( 1300). An analysis with reasonable priors result in better estimates of the excited state PDF and the moments, wherein we find evidence that the radial excitation of pion correlates with an almost two-fold increase in the momentum fraction of valence quarks. This proof-of-principle work establishes the viability of future lattice computations incorporating larger operator basis that can resolve the structural changes accompanying hadronic excitation.

No abstract

No abstract

In this paper, the dispersion relationship is derived by using the k • p method with the help of the perturbation theory, and we obtain the analytical expression in connection with the deformation potential. The calculation of the valence band of the biaxial strained Ge/(001)Si 1−x Gex is then performed. The results show that the first valence band edge moves up as Ge fraction x decreases, while the second valence band edge moves down. The band structures in the strained Ge/ (001)Si 0.4 Ge 0.6 exhibit significant changes with x decreasing in the relaxed Ge along the [0, 0, k] and the [k, 0, 0] directions. Furthermore, we employ a pseudo-potential total energy package (CASTEP) approach to calculate the band structure with the Ge fraction ranging from x = 0.6 to 1. Our analytical results of the splitting energy accord with the CASTEP-extracted results. The quantitative results obtained in this work can provide some theoretical references to the understanding of the strained Ge materials and the conduction channel design related to stress and orientation in the strained Ge pMOSFET.