Related papers: Neutron stars and the cosmological constant proble…
Based on tensions between the early and late time cosmology, we proposed a double valued cosmological constant which could undergo a phase transition in its history. It is named "double-$\Lambda$ Cold Dark Matter": $\Lambda\Lambda$CDM. An…
The cosmological evolution can be described in terms of directly measurable cosmological scalar parameters (deceleration $q$, jerk $j$, snap $s$, etc...) constructed out of high order derivatives of the scale factor. Their behavior at the…
This contribution reviews recent work on a new approach to the cosmological constant problem, which starts from the macroscopic behavior of a conserved relativistic microscopic variable q. First, the statics of the vacuum energy density is…
We investigate the effects of a magnetic field on the thermodynamics of a neutron system at finite density and temperature. Our main motivation is to deepen the understanding of the physics of a class of neutron stars known as magnetars,…
Neutron stars provide a natural laboratory for studying the properties of dense nuclear matter under extreme conditions. In this proceeding, we review our current understanding of dense isospin symmetric and asymmetric matter and neutron…
We summarize in this contribution to the the proceedings of "Compact Stars in the QCD Phase Diagram III (CSQCD III)", December 12-15, 2012, Guaruja, SP, Brazil the possibility of an scenario involving the existence of cosmic external agents…
The ohmic decay of magnetic fields confined within the crust of neutron stars is considered by incorporating both the effect of neutron star cooling and the effect of space-time curvature produced by the intense gravitational field of the…
The modern phase diagram of strongly interacting matter reveals a rich structure at high-densities due to phase transitions related to the chiral symmetry of quantum chromodynamics (QCD) and the phenomenon of color superconductivity. These…
Increasing improvements in the independent determinations of the Hubble constant and the age of the universe now seem to indicate that we need a small non-vanishing cosmological constant to make the two independent observations consistent…
In this work, we study the cosmological constant problem and Hubble tension in the void-dominated cosmology scenario \cite{Yusofi:2022hgg}. For this goal, we will first consider the cosmic voids in the cosmic web as interconnected ideal…
It is pointed out that a collider experiment involves a local contribution to the energy-momentum tensor, a circumstance which not a common feature of the current state of the Universe at large characterized by the cosmological constant…
We study how light scalar fields can change the stellar landscape by triggering a new phase of nuclear matter. Scalars coupled to nucleons can develop a non-trivial expectation value at finite baryon density. This sourcing of a scalar…
The effects of density dependence of the symmetry energy on the collective modes and dynamical instabilities of cold and warm nuclear and stellar matter are studied in the framework of relativistic mean-field hadron models. The existence of…
We investigate the effect of a cosmological constant on the gravothermal catastrophe in the Newtonian limit. A negative cosmological constant acts as a thermodynamic `destabilizer'. The Antonov radius gets smaller and the instability…
We study the decay of the cosmological constant in two spacetime dimensions through production of pairs. We show that the same nucleation process looks as quantum mechanical tunneling (instanton) to one Killing observer and as thermal…
We study the energy released from phase-transition induced collapse of neutron stars, which results in large amplitude stellar oscillations. To model this process we use a Newtonian hydrodynamic code, with a high resolution shock-capturing…
We present a pedagogic discussion on the role of novel phases of dense baryonic matter in ``neutron'' stars. Qualitative aspects of the physics that drives phase transitions and some of its astrophysical consequences are discussed.…
In many interesting models, including superstring theories, a negative vacuum energy is predicted. Although this effect is usually regarded as undesirable from a cosmological point of view, we show that this can be the basis for a new…
The study of cosmic phase transitions are of central interest in modern cosmology. In the standard model of cosmology the Universe begins in a very hot state, right after at the end of inflation via the process of reheating/preheating, and…
We present studies of the collapse of neutron stars that undergo a hadron-quark phase transition. A spherical Lagrangian hydrodynamic code has been written. As initial condition we take different neutron star configurations taking into…