21,028 research outputs found
Secondary-electron radiation accompanying hadronic GeV-TeV gamma-rays from supernova remnants
The synchrotron radiation from secondary electrons and positrons (SEPs)
generated by hadronic interactions in the shock of supernova remnant (SNR)
could be a distinct evidence of cosmic ray (CR) production in SNR shocks. Here
we provide a method where the observed gamma-ray flux from SNRs, created by
pion decays, is directly used to derive the SEP distribution and hence the
synchrotron spectrum. We apply the method to three gamma-ray bright SNRs. In
the young SNR RX J1713.7-3946, if the observed GeV-TeV gamma-rays are of
hadronic origin and the magnetic field in the SNR shock is mG,
the SEPs may produce a spectral bump at eV, exceeding the
predicted synchrotron component of the leptonic model, and a soft spectral tail
at keV, distinct from the hard spectral slope in the leptonic
model. In the middle-aged SNRs IC443 and W44, if the observed gamma-rays are of
hadronic origin, the SEP synchrotron radiation with G can
well account for the observed radio flux and spectral slopes, supporting the
hadronic origin of gamma-rays. Future microwave to far-infrared and hard X-ray
(>100keV) observations are encouraged to constraining the SEP radiation and the
gamma-ray origin in SNRs.Comment: 9 pages, 5 figures and 1 table, MNRAS accepte
Entanglement concentration for unknown atomic entangled states via entanglement swapping
An entanglement concentration scheme for unknown atomic entanglement states
is proposed via entanglement swapping in cavity QED. Because the interaction
used here is a large-detuned one between two driven atoms and a quantized
cavity mode, the effects of the cavity decay and thermal field have been
eliminated. These advantages can warrant the experimental feasibility of the
current scheme.Comment: 4 page
On q-deformed infinite-dimensional n-algebra
The -deformation of the infinite-dimensional -algebra is investigated.
Based on the structure of the -deformed Virasoro-Witt algebra, we derive a
nontrivial -deformed Virasoro-Witt -algebra which is nothing but a
sh--Lie algebra. Furthermore in terms of the pseud-differential operators on
the quantum plane, we construct the (co)sine -algebra and the -deformed
-algebra. We prove that they are the sh--Lie algebras for
the case of even . An explicit physical realization of the (co)sine
-algebra is given.Comment: 22 page
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