40,090 research outputs found
Global superscaling analysis of quasielastic electron scattering with relativistic effective mass
We present a global analysis of the inclusive quasielastic electron
scattering data with a superscaling approach with relativistic effective mass.
The SuSAM* model exploits the approximation of factorization of the scaling
function out of the cross section under quasifree conditions. Our
approach is based on the relativistic mean field theory of nuclear matter where
a relativistic effective mass for the nucleon encodes the dynamics of nucleons
moving in presence of scalar and vector potentials. Both the scaling variable
and the single nucleon cross sections include the effective mass as a
parameter to be fitted to the data alongside the Fermi momentum . Several
methods to extract the scaling function and its uncertainty from the data are
proposed and compared. The model predictions for the quasielastic cross section
and the theoretical error bands are presented and discussed for nuclei along
the periodic table from to : H, H, He, He,
C, Li, Be, Mg, Ni,
Y, Sn, Ta, W, Au, O, Al,
Ca, Ca, Fe, Pb, and U.
We find that more than 9000 of the total data fall within the
quasielastic theoretical bands. Predictions for Ti and Ar are
also provided for the kinematics of interest to neutrino experiments.Comment: 26 pages, 20 figures and 4 table
Interlayer hybridization and moir\'e superlattice minibands for electrons and excitons in heterobilayers of transition-metal dichalcogenides
Geometrical moir\'e patterns, generic for almost aligned bilayers of
two-dimensional (2D) crystals with similar lattice structure but slightly
different lattice constants, lead to zone folding and miniband formation for
electronic states. Here, we show that moir\'e superlattice (mSL) effects in
and
heterobilayers that feature alignment of the band edges are enhanced by
resonant interlayer hybridization, and anticipate similar features in twisted
homobilayers of TMDs, including examples of narrow minibands close to the
actual band edges. Such hybridization determines the optical activity of
interlayer excitons in transition-metal dichalcogenide (TMD) heterostructures,
as well as energy shifts in the exciton spectrum. We show that the resonantly
hybridized exciton (hX) energy should display a sharp modulation as a function
of the interlayer twist angle, accompanied by additional spectral features
caused by umklapp electron-photon interactions with the mSL. We analyze the
appearance of resonantly enhanced mSL features in absorption and emission of
light by the interlayer exciton hybridization with both intralayer A and B
excitons in , ,
, , and
.Comment: Final published version, with updated title and abstract, minor
corrections to equations, and 4 new figures adde
Separability conditions from the Landau-Pollak uncertainty relation
We obtain a collection of necessary (sufficient) conditions for a bipartite
system of qubits to be separable (entangled), which are based on the
Landau-Pollak formulation of the uncertainty principle. These conditions are
tested, and compared with previously stated criteria, by applying them to
states whose separability limits are already known. Our results are also
extended to multipartite and higher-dimensional systems.Comment: 20 page
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