A stringy perspective on the coincidence problem. (arXiv:2105.03426v1 [hep-th])
<a href="http://arxiv.org/find/hep-th/1/au:+Cunillera_F/0/1/0/all/0/1">Francesc Cunillera</a>, <a href="http://arxiv.org/find/hep-th/1/au:+Padilla_A/0/1/0/all/0/1">Antonio Padilla</a>
We argue that, for generic string compactifications, dark energy is likely to
signal the beginning of the end of our universe, perhaps even through
decompactification, with possible implications for the cosmological coincidence
problem. Thanks to the scarcity (absence?) of stable de Sitter vacua, dark
energy in string theory is expected to take the form of a quintessence field in
slow roll. As it rolls, a tower of heavy states will generically descend,
triggering an apocalyptic phase transition in the low energy cosmological
dynamics after at most a few hundred Hubble times. As a result, dark energy
domination cannot continue indefinitely and there is at least a percentage
chance that we find ourselves in the first Hubble epoch. We use a toy model of
quintessence coupled to a tower of heavy states to explicitly demonstrate the
breakdown in the cosmological dynamics as the tower becomes light. This occurs
through a large number of corresponding particles being produced after a
certain time, overwhelming quintessence. We also discuss some implications for
early universe inflation.
We argue that, for generic string compactifications, dark energy is likely to
signal the beginning of the end of our universe, perhaps even through
decompactification, with possible implications for the cosmological coincidence
problem. Thanks to the scarcity (absence?) of stable de Sitter vacua, dark
energy in string theory is expected to take the form of a quintessence field in
slow roll. As it rolls, a tower of heavy states will generically descend,
triggering an apocalyptic phase transition in the low energy cosmological
dynamics after at most a few hundred Hubble times. As a result, dark energy
domination cannot continue indefinitely and there is at least a percentage
chance that we find ourselves in the first Hubble epoch. We use a toy model of
quintessence coupled to a tower of heavy states to explicitly demonstrate the
breakdown in the cosmological dynamics as the tower becomes light. This occurs
through a large number of corresponding particles being produced after a
certain time, overwhelming quintessence. We also discuss some implications for
early universe inflation.
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