Title: Constraining dense matter properties from thermal and spin evolution of neutron stars

Abstract:  Neutron star interiors are the only laboratory to harbor cold (temperatures less than tens of MeV) and dense (densities higher than normal nuclear density but lower than those where perturbative QCD is applicable) matter in the universe. In this talk, I will report on our recent endeavors to answer the intriguing question: are exotic degrees of freedom realized in the densest cores of the most compact stars?

We analyze the thermal states of accreting neutron stars in quiescence, confining the studies within nucleons-only framework, and find the stringent limitation imposed by observation of the hottest and coldest sources disfavors the assumption without exotic matter. In addition, combining temperature and spin frequency data I will describe an interesting feature of hybrid stars with a sharp interface between nuclear matter mantle and quark matter core: capability of damping density oscillations e.g. r-modes in neutron stars that otherwise cannot be explained in the standard scenario of purely hadronic matter. These results we obtained could therefore provide theoretical predictions of the presence of exotic matter for future observations to confirm or rule out.