Vacuum fluctuation effects on asymmetric nuclear matter

The vacuum fluctuation (VF) effects on asymmetric nuclear matter are investigated. Masses of nucleons and mesons are modified in the nuclear medium by calculating the loop-diagram corrections and the density dependence of hadron masses is obtained. The relativistic Lagrangian density with the isovector scalar $\delta$ meson is used to calculate the nuclear equation of state (EOS) in the framework of the relativistic mean-field (RMF) approach, the effects of the in-medium hadron masses on the properties of neutron stars are finally studied. With the inclusion of the VF corrections, the nuclear EOS becomes softer and the neutron star masses are reduced.