Related papers: Compact dwarfs made of light-quark nuggets
White dwarfs (WDs) can be used as laboratories to test strong gravity and high-density regimes, once their equation of state is not so uncertain as the one of neutron stars. This makes them also a useful tool to constrain dark-matter…
3-flavor quark matter (strange quark matter; SQM) can be stable or metastable for a wide range of strong interaction parameters. If so, SQM can play an important role in cosmology, neutron stars, cosmic ray physics, and relativistic…
We study ultralight scalar fields with quadratic couplings to Standard-Model fermions and derive strong constraints from white-dwarf mass-radius data. Such couplings source scalar profiles inside compact stars, shift fermion masses, and can…
Strange quark matter in beta equilibrium at high densities is studied in a quark confinement model. Two equations of state are dynamically generated for the {\it same} set of model parameters used to describe the nucleon: one corresponds to…
Stable lumps of quark matter may be present in cosmic rays at a flux level, which can be detected by high precision cosmic ray experiments sensitive to anomalous "nuclei" with high mass-to-charge ratio. The properties of these lumps, called…
We reexamine the surface composition of strange stars. Strange quark stars are hypothetical compact stars which could exist if strange quark matter was absolutely stable. It is widely accepted that they are characterized by an enormous…
The present work is connected with the investigation of the origin and properties of compact astrophysical objects endowed with strangeness, with the objective of finding out their relevance in the formation and evolution of the universe.…
Astrophysicists distinguish between three different types of compact stars. These are white dwarfs, neutron stars, and black holes. The former contain matter in one of the densest forms found in the Universe which, together with the…
"Dark quark nuggets", a lump of dark quark matter, can be produced in the early universe for a wide range of confining gauge theories and serve as a macroscopic dark matter candidate. The two necessary conditions, a nonzero dark baryon…
We summarize masses and radii for a number of white dwarfs as deduced from a combination of proper motion studies, Hipparcos parallax distances, effective temperatures, and binary or spectroscopic masses. A puzzling feature of these data is…
Seven ultra low-mass and small-radius white dwarfs (LSPM J0815+1633, LP 240-30, BD+20 5125B, LP 462-12, WD J1257+5428, 2MASS J13453297+4200437, and SDSS J085557.46+053524.5) have been recently identified with masses ranging from $\sim$0.02…
We investigate the stability and $e^+e^-$ pair creation of supercritically charged superheavy nuclei, $ud$QM nuggets, strangelets, and strangeon nuggets based on Thomas-Fermi approximation. The model parameters are fixed by reproducing…
Strangelets (stable lumps of quark matter) can have masses and charges much higher than those of nuclei, but have very low charge-to-mass ratios. This is confirmed in a relativistic Thomas-Fermi model. The high charge allows astrophysical…
We study the stability of small strangelets by employing a simple model of strange matter as a gas of non-interacting fermions confined in a bag. We solve the Dirac equation and populate the energy levels of the bag one quark at a time. Our…
Pulsar-like objects are extremely compact, with an average density that exceeds nuclear saturation density, where the fundamental strong interaction plays an essential role, particularly in the low-energy regime. The internal structures and…
For a limited range of parameters, stable strange quark matter may be negatively charged in bulk due to one gluon exchange interactions. However, the reduction in strange quark occupation in the surface layer, which is responsible for…
We advocate an idea that ``non-baryonic" dark matter in form of nuggets made of standard model quarks and gluons (similar to the old idea of the Witten's strangelets) could play a crucial role in structure formation. The corresponding…
We investigate the dynamical behavior of strange quark matter (SQM) objects, such as stars and planets, when subjected to radial oscillations induced by tidal interactions in stellar systems. Our study demonstrates that SQM objects can…
We investigate compact objects formed by dark matter admixed with ordinary matter made of neutron star matter and white dwarf material. We consider non-self annihilating dark matter with an equation-of-state given by an interacting Fermi…
Forty years ago Witten suggested that dark matter could be composed of macroscopic clusters of strange quark matter. This idea was very popular for several years, but it dropped out of fashion once lattice QCD calculations indicated that…