31,318 research outputs found
Interpretation of the unprecedentedly long-lived high-energy emission of GRB 130427A
High energy photons (>100 MeV) are detected by the Fermi/LAT from GRB 130427A
up to almost one day after the burst, with an extra hard spectral component
being discovered in the high-energy afterglow. We show that this hard spectral
component arises from afterglow synchrotron-self Compton emission. This
scenario can explain the origin of >10 GeV photons detected up to ~30000s after
the burst, which would be difficult to be explained by synchrotron radiation
due to the limited maximum synchrotron photon energy. The lower energy
multi-wavelength afterglow data can be fitted simultaneously by the afterglow
synchrotron emission. The implication of detecting the SSC emission for the
circumburst environment is discussed.Comment: 4 pages, 2 figures, ApJL in pres
Three-generation neutrino oscillations in curved spacetime
Three-generation MSW effect in curved spacetime is studied and a brief
discussion on the gravitational correction to the neutrino self-energy is
given. The modified mixing parameters and corresponding conversion
probabilities of neutrinos after traveling through celestial objects of
constant densities are obtained. The method to distinguish between the normal
hierarchy and inverted hierarchy is discussed in this framework. Due to the
gravitational redshift of energy, in some extreme situations, the resonance
energy of neutrinos might be shifted noticeably and the gravitational effect on
the self-energy of neutrino becomes significant at the vicinities of spacetime
singularities.Comment: 25 pages, 5 figures, 2 tables. Some changes are made according to
referee's suggestions. The final version is to be published at Nuclear
Physics
Three-body interactions on a triangular lattice
We analyze the hard-core Bose-Hubbard model with both the three-body and
nearest neighbor repulsions on the triangular lattice. The phase diagram is
achieved by means of the semi-classical approximation and the quantum Monte
Carlo simulation. For a system with only the three-body interactions, both the
supersolid phase and one third solid disappear while the two thirds solid
stably exists. As the thermal behavior of the bosons with nearest neighbor
repulsion, the solid and the superfluid undergo the 3-state Potts and the
Kosterlitz-Thouless type phase transitions, respectively. In a system with both
the frustrated nearest neighbor two-body and three-body interactions, the
supersolid and one third solid revive. By tuning the strength of the three-body
interactions, the phase diagram is distorted, because the one-third solid and
the supersolid are suppressed.Comment: 6 pages, 11 figure
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