Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cosmological Surprises from Braneworld models of Dark Energy   Properties of Braneworld models of dark energy are reviewed. Braneworld
models admit the following interesting possibilities: (i) The effective
equation of state can be w < -1 as well as w > -1. In the former case the
expansion of the universe is well behaved at all times and the universe does
not run into a future `Big Rip' singularity which is usually encountered by
Phantom models. (ii) For a class of Braneworld models the acceleration of the
universe can be a transient phenomenon. In this case the current acceleration
of the universe is sandwiched between two matter dominated epochs. Such a
braneworld does not have a horizon in contrast to LCDM and most Quintessence
models. (iii) For a specific set of parameter values the universe can either
originate from, or end its existence in a Quiescent singularity, at which the
density, pressure and Hubble parameter remain finite, while the deceleration
parameter and all invariants of the Riemann tensor diverge to infinity within a
finite interval of cosmic time. (iv) Braneworld models of dark energy can
loiter at high redshifts: $6 \lleq z \lleq 40$. The Hubble parameter
decreasesduring the loitering epoch relative to its value in LCDM. As a result
the age of the universe at loitering dramatically increases and this is
expected to boost the formation of high redshift gravitationally bound systems
such as $10^9 M_\odot$ black holes at $z \sim 6$ and lower-mass black holes
and/or Population III stars at $z > 10$, whose existence could be problematic
within the LCDM scenario. (v) Braneworld models with a time-like extra
dimension bounce at early times thereby avoiding the initial `Big Bang
singularity'. (vi) Both Inflation and Dark Energy can be successfully unified
within a single scheme (Quintessential Inflation).

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The categories of this paper are: adap-org
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The categories of this paper are: nucl-th
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The categories of this paper are: math-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: acc-phys
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The categories of this paper are: cond-mat
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The categories of this paper are: nlin
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The categories of this paper are: funct-an
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The categories of this paper are: hep-lat
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The categories of this paper are: dg-ga
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: cs
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The categories of this paper are: hep-ex
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The categories of this paper are: stat