Speaker
Description
Observations of gravitational waves from neutron star mergers open up novel directions for exploring fundamental physics: they offer the first direct access to the structure of objects with a non-negligible contribution from vacuum energy to their total mass. The presence of such vacuum energy in the inner cores of neutron stars is a natural consequence of possible new QCD phases at large densities. This in turn leads to a change in tidal deformabilities which are measurable in the chirp signals of merging neutron stars, and for large chirp masses the effect of vacuum energy can be sizable. Measurements of this sort have the potential to provide a first test of the gravitational properties of vacuum energy independent of those obtained from the acceleration of the Universe, and also determine the size of the QCD contribution to vacuum energy in the Universe.
