17,491 research outputs found
Gravitational Perfect Fluid Collapse in Gauss-Bonnet Gravity
The Einstein Gauss-Bonnet theory of gravity is the low energy limit of
heterotic super-symmetric string theory. This paper deals gravitational
collapse of perfect fluid in Einstein Gauss-Bonnet gravity by considering the
Lemaitre - Tolman - Bondi metric. For this purpose, the closed form of exact
solution of equations of motion has been determined by using the conservation
of stress-energy tensor and the condition of marginally bound shells. It has
been investigated that the presence of Gauss-Bonnet coupling term
and pressure of the fluid modifies the structure and time formation of
singularity. In this analysis singularity form earlier than horizon, so end
state of the collapse is a naked singularity depending on the initial data. But
this singularity is weak and timelike that goes against the investigation of
general relativity.Comment: 16 pages, 3 Figures; some future research directions mentioned; to
appear in European Physical Journal
Colour Confinement and Deformed Baryons in Quantum Chromodynamics
The confinement of coloured entities in Quantum Chromodynamics (QCD) is
traced to colour singletness of the observed entities. This is believed to
arise from colour singlet state of quark-antiquark for mesons and a fully
colour antisymmetric state for baryons. This demands a spherically symmetric
baryon in the ground state. However it is pointed out that a deformed baryon in
the ground state has been found to be extremely successful phenomenology. There
are convincing experimental supports for a deformed nucleon as well. This means
that something has been missed in the fundamental theory. In this paper this
problem is traced to a new colour singlet state for baryons which has been
missed hitherto and incorporation of which provides a consistent justification
of a deformed baryon in the ground state. Interestingly this new colour singlet
state is global in nature.Comment: 5 pages, 1 figur
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