Neutron Stars

The detection of gravitational waves and the corresponding electromagnetic counterpart from a binary neutron star merger has provided for a new way to probe QCD in the cold dense regime. One particularly pressing constraint is the equation of state (EoS), which is poorly understood. In [1], we constructed an equation of state from a realistic holographic model. This results in a qualitatively reasonable phase diagram, and a fairly stiff EoS, i.e. with a very large speed of sound:

In [2], we combined the resulting EoS in the high density regime with a low density EoS coming from chiral effective theory. We subsequently used the resulting hybrid EoS to compute neutron star merger simulations for equal masses of 1.3 and 1.4 solar mass neutron stars, as shown below:

The resulting gravitational wave signal is sensitive to changes in the EoS, meaning that it can potentially be used to compare our EoS with observations from LIGO/VIRGO.