23,833 research outputs found
Multi chiral-doublets in one single nucleus
Adiabatic and configuration-fixed constraint triaxial relativistic mean field
(RMF) approaches are developed for the first time and a new phenomenon, the
existence of multi chiral-doublets (MD), i.e., more than one pairs of
chiral doublets bands in one single nucleus, is suggested for nuclei in A~100
region, typically for Rh, based on the triaxial deformations together
with their corresponding proton and neutron configurations.Comment: 10 pages, 4 figure
Progress on tilted axis cranking covariant density functional theory for nuclear magnetic and antimagnetic rotation
Magnetic rotation and antimagnetic rotation are exotic rotational phenomena
observed in weakly deformed or near-spherical nuclei, which are
respectivelyinterpreted in terms of the shears mecha-nism and two shearslike
mechanism. Since their observations, magnetic rotation and antimagnetic
rotation phenomena have been mainly investigated in the framework of tilted
axis cranking based on the pairing plus quadrupole model. For the last decades,
the covariant density functional theory and its extension have been proved to
be successful in describing series of nuclear ground-states and excited states
properties, including the binding energies, radii, single-particle spectra,
resonance states, halo phenomena, magnetic moments, magnetic rotation,
low-lying excitations, shape phase transitions, collective rotation and
vibrations, etc. This review will mainly focus on the tilted axis cranking
covariant density functional theory and its application for the magnetic
rotation and antimagnetic rotation phenomena.Comment: 53 pages, 19 figure
Orbital elements of barium stars formed through a wind accretion scenario
Taking the total angular momentum conservation in place of the tangential
momentum conservation, and considering the square and higher power terms of
orbital eccentricity e, the changes of orbital elements of binaries are
calculated for wind accretion scenario. These new equations are used to
quantitatively explain the observed (e,logP) properties of normal G, K giants
and barium stars. Our results reflect the evolution from G, K giant binaries to
barium binaries, moreover, the barium stars with longer orbital periods P>1600
days may be formed by accreting part of the ejecta from the intrinsic AGB stars
through wind accretion scenario.Comment: 7 pages, LaTex, 4 PS figures and 1 table included, accepted for
publication in A &
Hawking radiation, W-infinity algebra and trace anomalies
We apply the "trace anomaly method" to the calculation of moments of the
Hawking radiation of a Schwarzschild black hole. We show that they can be
explained as the fluxes of chiral currents forming a W-infinity algebra. Then
we construct the covariant version of these currents and verify that up to
order 6 they are not affected by any trace anomaly. Using cohomological methods
we show that actually, for the fourth order current, no trace anomalies can
exist. The results reported here are strictly valid in two dimensions.Comment: 22 pages, typos correcte
Low-field magnetotransport in graphene cavity devices
Confinement and edge structures are known to play significant roles in
electronic and transport properties of two-dimensional materials. Here, we
report on low-temperature magnetotransport measurements of lithographically
patterned graphene cavity nanodevices. It is found that the evolution of the
low-field magnetoconductance characteristics with varying carrier density
exhibits different behaviors in graphene cavity and bulk graphene devices. In
the graphene cavity devices, we have observed that intravalley scattering
becomes dominant as the Fermi level gets close to the Dirac point. We associate
this enhanced intravalley scattering to the effect of charge inhomogeneities
and edge disorder in the confined graphene nanostructures. We have also
observed that the dephasing rate of carriers in the cavity devices follows a
parabolic temperature dependence, indicating that the direct Coulomb
interaction scattering mechanism governs the dephasing at low temperatures. Our
results demonstrate the importance of confinement in carrier transport in
graphene nanostructure devices.Comment: 13 pages, 5 figure
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