Quantum pumping with adiabatically modulated barriers in graphene

We study the adiabatic quantum pumping characteristics in the graphene modulated by two oscillating gate potentials out of phase. The angular and energy dependence of the pumped current is presented. The direction of the pumped current can be reversed when a high barrier demonstrates stronger transparency than a low one, which results from the Klein paradox. The underlying physics of the pumping process is illuminated.Comment: 14 pages, 4 figure

Empirical information on nuclear matter fourth-order symmetry energy from an extended nuclear mass formula

We establish a relation between the equation of state (EOS) of nuclear matter and the fourth-order symmetry energy $a_{\rm{sym,4}}(A)$ of finite nuclei in a semi-empirical nuclear mass formula by self-consistently considering the bulk, surface and Coulomb contributions to the nuclear mass. Such a relation allows us to extract information on nuclear matter fourth-order symmetry energy $E_{\rm{sym,4}}(\rho_0)$ at normal nuclear density $\rho_0$ from analyzing nuclear mass data. Based on the recent precise extraction of $a_{\rm{sym,4}}(A)$ via the double difference of the "experimental" symmetry energy extracted from nuclear masses, for the first time, we estimate a value of $E_{\rm{sym,4}}(\rho_0) = 20.0\pm4.6$ MeV. Such a value of $E_{\rm{sym,4}}(\rho_0)$ is significantly larger than the predictions from mean-field models and thus suggests the importance of considering the effects of beyond the mean-field approximation in nuclear matter calculations.Comment: 7 pages, 1 figure. Presentation improved and discussions added. Accepted version to appear in PL

Disintegration of an Eruptive Filament via Interactions with Quasi-Separatrix Layers

The disintegration of solar filaments via mass drainage is a frequently observed phenomenon during a variety of filament activities. It is generally considered that the draining of dense filament material is directed by both gravity and magnetic field, yet the detailed process remains elusive. Here we report on a partial filament eruption during which filament material drains downward to the surface not only along the filament's legs, but to a remote flare ribbon through a fan-out curtain-like structure. It is found that the magnetic configuration is characterized by two conjoining dome-like quasi-sepratrix layers (QSLs). The filament is located underneath one QSL dome, whose footprint apparently bounds the major flare ribbons resulting from the filament eruption, whereas the remote flare ribbon matches well with the other QSL dome's far-side footprint. We suggest that the interaction of the filament with the overlying QSLs results in the splitting and disintegration of the filament.Comment: Accepted for publication in SCIENCE CHINA Physics, Mechanics & Astronom