We have calculated the properties of nuclear matter in a self-consistent manner with a quark-meson coupling mechanism incorporating the structure of nucleons in vacuum through a relativistic potential model; where the dominant confining interaction for the free independent quarks inside a nucleon is represented by a phenomenologically average potential in equally mixed scalar-vector harmonic form. Corrections due to spurious center of mass motion as well as those due to other residual interactions, such as the one gluon exchange at short distances and quark-pion coupling arising out of chiral symmetry restoration, have been considered in a perturbative manner to obtain the nucleon mass in vacuum. The nucleon-nucleon interaction in nuclear matter is then realized by introducing additional quark couplings to σ and ω mesons through mean field approximations. The relevant parameters of the interaction are obtained self-consistently while realizing the saturation properties such as the binding energy, pressure, and compressibility of the nuclear matter. We also discuss some implications of chiral symmetry in nuclear matter along with the nucleon and nuclear σ term and the sensitivity of nuclear matter binding energy with variations in the light quark mass.

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The possibility of the appearance of ∆(1232) isobars in neutron star matter and the so called ∆ puzzle is investigated in a relativistic quark model where the confining interaction for quarks inside a baryon is represented by a phenomenological average potential in an equally mixed scalar-vector harmonic form. The hadron-hadron interaction in nuclear matter is then realized by introducing additional quark couplings to σ, ω, and ρ mesons through mean-field approximations. The hyperon couplings are fixed from the hyperon optical potentials at saturation density. Effects of moderate variations in the ∆-ω and ∆-ρ coupling strength on the critical density of forming ∆ resonances and on the mass-radius relation of neutron stars is studied. We have also made an attempt to study the impact of in-medium mass variations of the ∆ baryon on the structure of neutron stars. It is observed that within the constraints of the mass of the precisely measured massive pulsars, PSR J0348+0432 and PSR J1614-2230, neutron stars with a composition of both ∆ isobars and hyperons is possible in the present model.

We study nuclear symmetry energy and the thermodynamic instabilities of asymmetric nuclear matter in a self-consistent manner by using a modified quark-meson coupling model where the confining interaction for quarks inside a nucleon is represented by a phenomenologically averaged potential in an equally mixed scalar-vector harmonic form. The nucleon-nucleon interaction in nuclear matter is then realized by introducing additional quark couplings to σ, ω, and ρ mesons through mean-field approximations. We find an analytic expression for the symmetry energy Esym as a function of its slope L. Our result establishes a linear correlation between L and Esym. We also analyze the constraint on neutron star radii in (pn) matter with β equilibrium. PACS numbers: 26.60.+c, 21.65.Qr, 95.30.Tg