Dr Gergely Gábor Barnaföldi (Wigner RCP of the HAS)
Astrophysical measurements regarding compact stars are becoming more and more accurate. The NICER experiment deployed on ISS on 14 June 2017 NASA (2017) will provide data that will enable the determination of compact star radius with less than 10\% error Ozel et al. This poses new challenges to nuclear models aiming to explain the structure of super dense nuclear matter found in neutron stars, because effects which earlier measurements was not able to resolve may became detectable. In the same time detailed studies of the QCD phase diagram shows the importance of bosonic quantum fluctuations in the cold dense matter equation of state. In this talk we build on our earlier work which introduced a new technique to calculate the effect of bosonic quantum fluctuations on the equation of state and thermodynamical quantities. Using a demonstrative model of one bosonic and one fermionic degree of freedom coupled by Yukawa coupling we show the effect of bosonic quantum fluctuations on compact star observables such as mass, radius and compactness. We have also calculated the difference in the value of compressibility which is caused by quantum fluctuations. The above mentioned quantities are calculated in mean field, one-loop and in high order many loop approximation. The results show that the magnitude of these effects is in the range of 4-5\%, which place it into the region where modern measurements may detect it. This forms a base for further investigations that how these results carry over to more complicated (e.g. Walecka-like) models.