Probing Crystalline Color Superconducting Phase of Quark Matter through Universal Relations for Hybrid Stars

The nature of the dense matter equation of state remains an open question, as physicists
from a variety of disciplines attempt to tackle this question from different perspectives,
especially via the study of neutron stars (NS). At the high densities associated with NS
cores, crystalline color-superconducting (CCS) phases of quark matter could possibly occur
from LOFF pairing of deconfined quarks [1]. The rigid behavior of this crystalline structure
causes the tidal deformation of neutron stars to be less than fluid stars, causing deviations
in the Love-C universal relations describing NS. Implementation of the rigidity of CCS phase
via density-dependent shear modulus into constant sound speed models developed by [2]
was conducted to investigate the deviation of these models from the universal relations.
Models that agreed strongly with observational constraints on NS masses and radii showed
upward of 10% fractional deviation from the best fit for the Love-C universal relation. This
indicates that better measurements of the tidal Love number and compactness could enable
the constraint of the parameters describing CCS equation of state, furthering our knowledge
of the behavior of matter at the highest densities in the universe.