19,092 research outputs found
Thermal and Non-thermal radiation from pulsars: hints of physics
Thermal and non-thermal radiation from pulsars carries significant
information from surface and would have profound implications on the state of
dense matter in compact stars. For the non-thermal radio emission, subpulse
drifting phenomena suggest the existence of Ruderman-Sutherland-like
gap-sparking and strong binding of particles on pulsar polar caps. While
conventional neutron star models can hardly provide such a high binding energy,
the strong self-bound surface of quark-cluster stars can naturally solve this
problem. As for the thermal one, the featureless X-ray spectra of pulsars may
indicate a bare surface without atmosphere, and the ultrarelativistic fireball
of gamma-ray bursts and supernovae would also require strong self-bound
surfaces. Recent achievements in measuring pulsar mass and mass-radius relation
further indicate a stiff equation of state and a self-bound surface. Therefore,
we conjecture that matters inside pulsar-like compact stars could be in a
quark-cluster phase. The surface of quark-cluster stars is chromatically
confined and could initially be bare. Such a surface can not only explain above
features, but may also promote a successful core-collapse supernova, and the
hydro-cyclotron oscillation of the electron sea above the surface could be
responsible for those absorption features detected in the X-ray spectrum.Comment: 4 pages, contribution to the ERPM conferences, Zielona Gora, April
201
Quiver Matrix Mechanics for IIB String Theory (I): Wrapping Membranes and Emergent Dimension
In this paper we present a discrete, non-perturbative formulation for type
IIB string theory. Being a supersymmetric quiver matrix mechanics model in the
framework of M(atrix) theory, it is a generalization of our previous proposal
of compactification via orbifolding for deconstructed IIA strings. In the
continuum limit, our matrix mechanics becomes a -dimensional Yang-Mills
theory with 16 supercharges. At the discrete level, we are able to construct
explicitly the solitonic states that correspond to membranes wrapping on the
compactified torus in target space. These states have a manifestly
SL(2,\integer)-invariant spectrum with correct membrane tension, and give
rise to an emergent flat dimension when the compactified torus shrinks to
vanishing size.Comment: LaTeX 2e; 39 pages, 3 eps figures. v2: typos corrected; references
added; identification of certain membrane states added. v3: minor corrections
on membrane state
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