Speaker
Erik Verlinde
(University of Amsterdam)
Description
In Anti-de Sitter space the emergence of gravity relies on
the area law for entanglement entropy. Using insights from
tensor networks and string theory we argue that de Sitter
space contains a volume law contribution to the entropy,
which overtakes the area law precisely at the cosmological
horizon. Due the competition between area and volume law
entanglement the microscopic states do not thermalise at
sub-Hubble scales. When matter is included, this causes a
memory effect in the form of an displacement of the entropy
density. As a result the emergent laws of gravity contain,
in addition to the familiar force law, an `elastic response'
due to the entropy displacement. We estimate the strength of
this extra `dark gravitational force' in terms the
(baryonic) mass and the Hubble acceleration scale, and find
good agreement with observed phenomena in galaxies and
clusters.
