Effect of quantum fluctuations in the high-energy cold nuclear equation of state and in compact star observables
We present a functional renormalization group (FRG) calculation of the equation of state (EoS) using our novel technique to treat fluctuations at finite chemical potential. The goal of this calculation was to provide a proof of concept for this technique as well as to estimate the size of the quantum effects in the equation of state and compact star parameters. We used the simplest nontrivial model where massless fermions are coupled to scalars through Yukawa coupling. We compared our results to the one-loop and the mean-field approximations of the same model and other high-density nuclear matter equations of state. We found a 10 -20 % difference in the EoS between these approximations. We have also calculated the mass-radius relation for a compact star using the Tolmann-Oppenheimer-Volkov equation with this EoS and observed a ∼5 % effect due to quantum fluctuations.