Theoretical priors in scalar-tensor cosmologies: thawing quintessence

**of**the Universe can be characterized in terms

**of**an extra, time dependent, component

**of**the universe -- dark energy. The simplest proposal for dark energy is a scalar-tensor theory -- quintessence -- which consists

**of**a scalar field, $\phi$, whose dynamics is solely dictated by its potential, $V(\phi)$. Such a theory can be uniquely characterized by the

**equation**

**of**

**state**

**of**the scalar field energy momentum-tensor. We find the time dependence

**of**the

**equation**

**of**

**state**for a broad family

**of**potentials and, using this information, we propose an analytic prior distribution for the most commonly used parametrization. We show that this analytic prior can be used to accurately predict the distribution

**of**observables for the next generation

**of**cosmological surveys. Including the theoretical priors in the comparison with observations considerably improves the constraints on the

**equation**

**of**

**state**.

5/10 relevant

arXiv

Neutron rich matter in the laboratory and in the heavens after GW170817

**of**the neutron star merger GW170817 advanced our understanding

**of**r-process nucleosynthesis and the

**equation**

**of**

**state**(EOS)

**of**neutron rich matter. Simple neutrino physics suggests that supernovae are not the site

**of**the main r-process. Instead, the very red color

**of**the kilonova associated with GW170817 shows that neutron star (NS) mergers are an important r-process site. We now need to measure the masses and beta decay half-lives

**of**very neutron rich heavy nuclei so that we can more accurately predict the abundances

**of**heavy elements that are produced. This can be done with new radioactive beam accelerators such as the Facility for Rare Isotope Beams (FRIB). GW170817 provided information on the deformability

**of**NS and the

**equation**

**of**

**state**

**of**dense matter. The PREX II experiment will measure the neutron skin

**of**${}^{208}$Pb and help constrain the low density EOS. As the sensitivity

**of**gravitational wave detectors improve, we expect to observe many more events. We look forward to exciting advances and surprises!

4/10 relevant

arXiv

Neutron star under homotopy perturbation method

**equation**for isotropic and spherically symmetric system via homotopy perturbation method (HPM). Using the mass function we construct a stellar model which can be determined from the

**equation**

**of**

**state**(EOS) parameter ($\omega$) and a model parameter ($n$). With the help

**of**Einstein field

**equations**we develop three solutions which can describe different properties and the core-crust structure

**of**neutron star (NS). Solution I is valid for NS having the inner and outer radius near the surface

**of**the star. The star is physical up to the inner radius whereas negative density occurs and the energy conditions are violated in the upper region from the inner to outer radius. Solution II represents NS with high gravitational redshift as well as compactification factor. All the features

**of**NS can be given by solution III which involves only the EOS parameter. Our model predicts maximum mass for a NS with the central density $5.5\times10^{15}~g/cm^{3}$ and surface redshift 0.69 is to be $2.01~M_\odot$ for the EOS parameter $\omega=0.73$. The predicted range for the surface redshift is $0.57

4/10 relevant

arXiv

Combining magneto-hydrostatic constraints with Stokes profiles inversions

**equation**can be used to infer the temperature $T$, line-of-sight velocity $v_{\rm los}$, and magnetic field $\rm{\bf B}$ as a function

**of**the continuum optical-depth $\tau_{\rm c}$. However, they do not directly provide the gas pressure $P_{\rm g}$ or density $\rho$. In order to obtain these latter parameters, inversion codes rely instead on the assumption

**of**hydrostatic equilibrium (HE) in addition to the

**equation**

**of**

**state**(EOS). Unfortunately, the assumption

**of**HE is rather unrealistic across magnetic field lines. This is because the role

**of**the Lorentz force, among other factors, is neglected. This translates into an inaccurate conversion from optical depth $\tau_{\rm c}$ to geometrical height $z$. We aim at improving this conversion via the application

**of**magneto-hydrostatic (MHS) equilibrium instead

**of**HE. We develop a method to solve the momentum

**equation**under MHS equilibrium (i.e., taking the Lorentz force into account) in three dimensions. The method is based on the solution

**of**a Poisson-like

**equation**. Considering the gas pressure $P_{\rm g}$ and density $\rho$ from three-dimensional magneto-hydrodynamic (MHD) simulations

**of**sunspots as a benchmark, we compare the results from the application

**of**HE and MHS equilibrium. We find that HE retrieves the gas pressure and density within an order

**of**magnitude

**of**the MHD values in only about 47 \%

**of**the domain. This translates into an error

**of**about $160-200$ km in the determination

**of**the $z-\tau_{\rm c}$ conversion. On the other hand, the application

**of**MHS equilibrium allows determination

**of**$P_{\rm g}$ and $\rho$ within an order

**of**magnitude in 84 \%

**of**the domain. In this latter case, the $z-\tau_{\rm c}$ conversion is obtained with an accuracy

**of**$30-70$ km.

4/10 relevant

arXiv

Fast Rotating Relativistic Stars: Spectra and Stability without Approximation

**equation**

**of**

**state**via all possible observables. Expand abstract.

**of**relativistic stars are studied by taking into account, for the first time, the contribution

**of**a dynamic space-time. The study is based on the linearised version

**of**Einstein's

**equations**and via this approach the oscillation frequencies, the damping and growth times as well as the critical values for the onset

**of**the secular (CFS) instability are presented. The ultimate universal relations for asteroseismology are derived which can lead to relations involving the moment

**of**inertia and Love numbers in an effort to uniquely constrain the

**equation**

**of**

**state**via all possible observables. The results are important for all stages

**of**neutron star's life but especially to nascent or post-merger cases.

4/10 relevant

arXiv

The Shock Physics of Giant Impacts: Key Requirements for the **Equations**
**of** **State**

**equations**

**of**

**state**(EOS). During the giant impact stage

**of**planet formation, rocky planets are melted and partially vaporized. However, most EOS models fail to reproduce experimental constraints on the thermodynamic properties

**of**the major minerals over the required phase space. Here, we present an updated version

**of**the widely-used ANEOS model that includes a user-defined heat capacity limit in the thermal free energy term. Our revised model for forsterite (Mg$_2$SiO$_4$), a common proxy for the mantles

**of**rocky planets, provides a better fit to material data over most

**of**the phase space

**of**giant impacts. We discuss the limitations

**of**this model and the Tillotson

**equation**

**of**state, a commonly used alternative model.

4/10 relevant

arXiv

Efectos del campo magn'etico en un gas de bosones vectoriales neutros: aplicaciones astrof\'isicas

**equations**

**of**

**state**of this object, we develope a system of

**equation**s to describe the hydrodynamic equilibrium -- the structure -- of spheroidal compact objects starting from an axisymmetric metric. Expand abstract.

**of**the magnetic field on neutron stars matter are studied, assuming that the neutrons inside these stars are partially or totally paired forming neutral vector bosons. The main effects

**of**the magnetic field on the gas are, first, to favor the phase transition to the Bose-Eintein condensation, and second, to split the pressure in two components, one parallel and the other perpendicular to the magnetic axis, giving rise to anisotropic

**equations**

**of**

**state**. At low densities or high magnetic fields, the lowest pressure can be negative, and the boson system becomes susceptible to suffer a transverse magnetic collapse. On the other hand, when the temperature is low enough, the gas can spontaneously magnetize. The

**equations**

**of**

**state**

**of**the magnetized gas

**of**neutral vector bosons are applied, firstly, to study the magnetic collpase

**of**an ideal gas

**of**neutrons, electrons and protons (npe gas) in which the nucleons are partially bosonized. From the results obtained, a model for the ejection

**of**matter out

**of**the star and the formation

**of**astrophysical jets is proposed. Subsequently, the

**equations**

**of**

**state**

**of**the magnetized vector gas are used to study the magnetic field influence on the structure (mass, radius and deformation)

**of**Bose-Einsten condensate stars, that is,

**of**compact objects composed entirely by a neutron gas fully bosonized. In order to appropriately take into account the magnetic anisotropy in the

**equations**

**of**

**state**

**of**this object, we develope a system

**of**

**equations**to describe the hydrodynamic equilibrium -- the structure --

**of**spheroidal compact objects starting from an axisymmetric metric. The obtained results validate the bosons self-magnetization as a feasible source for the magnetic field

**of**compact objects.

5/10 relevant

arXiv

Implications **of** the fermion vacuum term in the extended SU(3) Quark
Meson model on compact stars properties

**of**the fermion vacuum term in the SU(3) quark meson model on the

**equation**

**of**

**state**and determine the vacuum parameters for various sigma meson masses. We examine its influence on the

**equation**

**of**

**state**and on the resulting mass radius relations for compact stars. The tidal deformability $\Lambda$

**of**the stars is studied and compared to the results

**of**the mean field approximation. Parameter sets which fulfill the tidal deformability bounds

**of**GW170817 together with the observed two solar mass limit turn out to be restricted to a quite small parameter range in the mean field approximation. The extended version

**of**the model does not yield solutions fulfilling both constraints. Furthermore, no first order chiral phase transition is found in the extended version

**of**the model, not allowing for the twin star solutions found in the mean field approximation.

4/10 relevant

arXiv

Contact Geometry and Thermodynamics **of** Black Holes in AdS

**equations**

**of**

**state**of general black holes in AdS are shown to emerge from the high temperature ideal gas limit

**equation**s, via suitable deformations induced by contact vector fields. Expand abstract.

**of**extended phase space thermodynamics

**of**black holes in Anti de Sitter (AdS) space-time, from the contact geometry point

**of**view. Thermodynamics

**of**black holes can be understood within the framework

**of**contact geometry as flows

**of**vector fields generated by Hamiltonian functions on equilibrium submanifolds in the extended phase space, that naturally incorporates the structure

**of**a contact manifold. Deformations induced by the contact vector fields are used to construct various maps among thermodynamic quantities. Thermodynamic variables and

**equations**

**of**

**state**

**of**Schwarzschild black holes are mapped to that

**of**Reissner-Nordstrom black holes in AdS, with charge as the deformation parameter. In addition, the

**equations**

**of**

**state**

**of**general black holes in AdS are shown to emerge from the high temperature ideal gas limit equations, via suitable deformations induced by contact vector fields. The Hamilton-Jacobi formalism analogous to mechanics is set up and the corresponding characteristic curves

**of**contact vector fields are explicitly obtained, to model thermodynamic processes

**of**black holes. Extension to thermodynamic cycles in this framework is also discussed.

4/10 relevant

arXiv

Three-dimensional **equations** **of** generalized dynamics of 18-fold symmetry
soft-matter quasicrystals

**equations**present some important meaning in the study on thermodynamics

**of**the matter which is also introduced. Expand abstract.

**of**governing

**equations**

**of**generalized dynamics

**of**18-fold symmetry soft-matter quasicrystals, according to the dynamics basis there are first and second phason elementary excitations apart from phonons and fluid phonon. In the derivation, the group representation theory is a key point. The complete form

**of**the theory includes an

**equation**

**of**

**state**. The governing

**equations**present some important meaning in the study on thermodynamics

**of**the matter which is also introduced.

4/10 relevant

arXiv