English
Related papers

Related papers: Neutron Stars and the Cosmological Constant Proble…

200 papers

Neutron stars are supposed to be mainly formed by a neutron superfluid. The angular momentum is given by the vortex array within the fluid, and a good account of the observable effects is determined by its coupling with the crust. In this…

High Energy Physics - Theory · Physics 2007-05-23 H. Casini , R. Montemayor

The discovery of cosmic acceleration has presented a unique challenge for cosmologists. As observational cosmology forges ahead, theorists have struggled to make sense of a standard model that requires extreme fine tuning. This challenge is…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-02 Chanda Prescod-Weinstein , Niayesh Afshordi , Michael L. Balogh

Neutron stars are valuable laboratories for the study of dense matter. Recent observations have uncovered both massive and low-mass neutron stars and have also set constraints on neutron star radii. The largest mass measurements are…

Nuclear Theory · Physics 2013-05-16 James M. Lattimer

We study slowly-rotating neutron stars in ghost-free massive bigravity. This theory modifies General Relativity by introducing a second, auxiliary but dynamical tensor field that couples to matter through the physical metric tensor through…

General Relativity and Quantum Cosmology · Physics 2018-02-14 Andrew Sullivan , Nicolas Yunes

We develop the general theory of stars in Saa's model of gravity with propagating torsion and study the basic stationary state of neutron star. Our numerical results show that the torsion force decreases the role of the gravity in the star…

General Relativity and Quantum Cosmology · Physics 2010-11-19 T. Boyadjiev , P. Fiziev , S. Yazadjiev

The macroscopic model is formulated for a neutron star (NS) as a perfect liquid drop at the equilibrium. We use the leptodermic approximation $a/R\ll 1$, where $a$ is the crust thickness of the effective NS surface (ES), and $R$ is the mean…

Nuclear Theory · Physics 2025-08-07 A. G. Magner , S. P. Maydanyuk , A. Bonasera , H. Zheng , T. Depastas , A. I. Levon , U. V. Grygoriev

We study neutron star configurations in a simple shift-symmetric subfamily of degenerate higher-order scalar-tensor (DHOST) theories, whose deviations from General Relativity (GR) are characterized by a single parameter. We compute the…

General Relativity and Quantum Cosmology · Physics 2022-11-09 Hamza Boumaza , David Langlois

Despite its elegance, the theory of General Relativity is subject to experimental, observational, and theoretical scrutiny to arrive at tighter constraints or an alternative, more preferred theory. In alternative gravity theories, the…

General Relativity and Quantum Cosmology · Physics 2023-09-12 Bhaskar Biswas , Evangelos Smyrniotis , Ioannis Liodis , Nikolaos Stergioulas

The realistic models of neutron stars are considered for simple $R+\alpha R^2$ gravity and equivalent Brance-Dicke theory with dilaton field in Einsein frame. For negative values of $\alpha$ we have no acceptable results from astrophysical…

General Relativity and Quantum Cosmology · Physics 2018-12-27 Artyom V. Astashenok , Alexey S. Baigashov , Sergey A. Lapin

An important and long-standing puzzle in the history of modern physics is the gross inconsistency between theoretical expectations and cosmological observations of the vacuum energy density, by at least 60 orders of magnitude, otherwise…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-25 Ali Narimani , Niayesh Afshordi , Douglas Scott

The stellar compactness, that is, the dimensionless ratio between the mass and radius of a compact star, $\mathcal{C} := M/R$, plays a fundamental role in characterising the gravitational and nuclear-physics aspects of neutron stars. Yet,…

General Relativity and Quantum Cosmology · Physics 2026-01-21 Luciano Rezzolla , Christian Ecker

Testing the constancy of the gravitational constant G has been a longstanding fundamental question in natural science. As first suggested by Jofr\'{e}, Reisenegger and Fern\'{a}ndez [1], Dirac's hypothesis of a decreasing gravitational…

Nuclear Theory · Physics 2008-11-26 P. G. Krastev , B. A. Li

A pure nucleonic equation of state (EoS) for beta equilibrated charge neutral neutron star (NS) matter is determined using density dependent effective NN interaction. This EoS is found to satisfy both the constraints from the observed…

Nuclear Theory · Physics 2011-05-11 Partha Roy Chowdhury

We derive the empirical formulas for the neutron star mass and gravitational redshift as a function of the central density and specific combination of the nuclear saturation parameters, which are applicable to the stellar models constructed…

Nuclear Theory · Physics 2022-03-23 Hajime Sotani , Hajime Togashi

The equation of state (EoS) of neutron matter plays a decisive role to understand the neutron star properties and the gravitational waves from neutron star mergers. At sufficient densities, the appearance of hyperons generally softens the…

Nuclear Theory · Physics 2025-02-21 Hui Tong , Serdar Elhatisari , Ulf-G. Meißner

The understanding of stellar structure represents the crossroads of our theories of the nuclear force and the gravitational interaction under the most extreme conditions observably accessible. It provides a powerful probe of the strong…

General Relativity and Quantum Cosmology · Physics 2020-09-15 Gonzalo J. Olmo , Diego Rubiera-Garcia , Aneta Wojnar

Searches for continuous gravitational waves from \textit{unknown} Galactic neutron stars provide limits on the shapes of neutron stars. A rotating neutron star will produce gravitational waves if asymmetric deformations exist in its…

High Energy Astrophysical Phenomena · Physics 2021-11-09 Brendan T. Reed , Alex Deibel , C. J. Horowitz

Neutron stars are some of the densest manifestations of massive objects in the universe. They are ideal astrophysical laboratories for testing theories of dense matter physics and provide connections among nuclear physics, particle physics…

Astrophysics · Physics 2011-05-05 J. M. Lattimer , M. Prakash

Models of neutron stars are considered in the case of a uniform density distribution. An algebraic equation, valid for any equation of state, is obtained. This equation allows one to find the approximate mass of a star of a given density…

High Energy Astrophysical Phenomena · Physics 2023-11-14 G. S. Bisnovatyi-Kogan , E. A. Patraman

In recent years, modified gravity theories have gained significant attention as potential replacements for the general theory of relativity. Neutron stars, which are dense compact objects, provide ideal astrophysical laboratories for…

General Relativity and Quantum Cosmology · Physics 2023-07-20 K. Nobleson , Sarmistha Banik , Tuhin Malik