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Related papers: Constraining and applying a generic high-density e…

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In this conference-proceedings contribution, we review recent advances in placing model-independent constraints on the properties of cold and dense QCD matter inside neutron stars. In addition to introducing new bounds for the Equation of…

High Energy Astrophysical Phenomena · Physics 2019-04-03 Eemeli Annala , Tyler Gorda , Aleksi Kurkela , Joonas Nättilä , Aleksi Vuorinen

We show how observations of gravitational waves from binary neutron star (BNS) mergers over the next few years can be combined with insights from nuclear physics to obtain useful constraints on the equation of state (EoS) of dense matter,…

High Energy Astrophysical Phenomena · Physics 2019-10-23 Michael McNeil Forbes , Sukanta Bose , Sanjay Reddy , Dake Zhou , Arunava Mukherjee , Soumi De

Pulse profile modeling of X-ray data from NICER is now enabling precision inference of neutron star mass and radius. Combined with nuclear physics constraints from chiral effective field theory ($\chi$EFT), and masses and tidal…

The effects of the presence of hyperons and a phase transition to deconfined quark matter on the speed of sound in neutron stars is investigated. For this purpose a composite description consisting of a model of the covariant field theory…

Nuclear Theory · Physics 2022-07-05 R. M. Aguirre

We propose a new equation of state for nuclear matter based on a generalized Skyrme model which is consistent with all current constraints on the observed properties of neutron stars. This generalized model depends only on two free…

We investigate the causal limit of maximum mass for stars in the framework of$f(R)$ gravity. We choose a causal equation of state, with variable speed of sound, and with the transition density and pressure corresponding to the SLy equation…

General Relativity and Quantum Cosmology · Physics 2021-04-07 A. V. Astashenok , S. Capozziello , S. D. Odintsov , V. K. Oikonomou

$\phi$CDM models provide an alternative to the standard $\Lambda$CDM paradigm, while being physically better motivated. These models lead to a time-dependent speed of sound for dark energy that is difficult to replicate by $w$CDM…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-29 Olga Avsajanishvili , Gennady Y. Chitov , Tina Kahniashvili , Sayan Mandal , Lado Samushia

We introduce a high-performance linear-scaling electronic structure method that employs chromatic superposition states (CSS) as a low-dimensional, high-fidelity representation, which can be orders of magnitude smaller than the full Hilbert…

Materials Science · Physics 2026-05-21 Zhikang Jiang , Zhizhi Xiao , Mingfa Tang , Weiyu Li , Zhaoru Sun , Ke Xia , Youqi Ke

Recently, Tsallis, R\'{e}nyi and Sharma-Mitall and entropies have widely been used to study the gravitational and cosmological setups. We consider a flat FRW universe with linear interaction between dark energy and dark matter. We discuss…

General Physics · Physics 2019-01-08 M. Younas , Abdul Jawad , Saba Qummer , H. Moradpour , Shamaila Rani

We consider here quark matter equation of state in a relativistic harmonic confinement model at zero temperature. The same is considered to study phase transition of neutron matter to quark matter at high densities. This, along with a…

High Energy Physics - Phenomenology · Physics 2009-10-28 S. B. Khadkikar , A. Mishra , H. Mishra

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…

Nuclear Theory · Physics 2025-04-01 Rajesh Kumar , Veronica Dexheimer , Johannes Jahan

The speed of sound refers to the rate at which information travels from one point to another. It is a positive quantity and bounded by causality. It is defined as the rate of change of pressure with respect to the system's density. In this…

High Energy Astrophysical Phenomena · Physics 2026-01-19 Anshuman Verma , Asim Kumar Saha , Ritam Mallick

In this article, we attempt to describe cosmic late-time acceleration of the universe in the framework of $f(R,L_m)$ gravity by using an effective equation of state when the account is taken of bulk viscosity. We presume a non-linear…

General Relativity and Quantum Cosmology · Physics 2023-03-31 Lakhan V. Jaybhaye , Raja Solanki , Sanjay Mandal , Pradyumn Kumar Sahoo

We derive constraints on the neutrino mass using a variety of recent cosmological datasets, including DESI BAO, the full-shape analysis of the DESI matter power spectrum and the one-dimensional power spectrum of the Lyman-$\alpha$ forest…

The existence of quark matter inside the heaviest neutron stars has been the topic of numerous recent studies, many of them suggesting that a phase transition to strongly interacting conformal matter inside neutron stars is feasible. Here…

High Energy Astrophysical Phenomena · Physics 2023-08-04 János Takátsy , Péter Kovács , György Wolf , Jürgen Schaffner-Bielich

Identifying new observational probes to constrain cosmological parameters has become an important goal in modern cosmology. In this work, we explore the potential of the cosmic star formation rate density (SFRD), compiled over the redshift…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-21 Miguel Moyses , Rafael C. Nunes

The interior of neutron stars contains matter at the highest densities realized in our Universe. Interestingly, theoretical studies of dense matter, in combination with the existence of two solar mass neutron stars, indicate that the speed…

It is well known that a spherically symmetric compact star whose energy density decreases monotonically possesses an upper bound on its mass-to-radius ratio, $2M/R\leq 8/9$. However, field configurations typically will not be compact. Here…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Shahar Hod

We investigate the possibility of using cosmological observations to probe and constrain an imperfect dark energy fluid. We consider a general parameterization of the dark energy component accounting for an equation of state, speed of sound…

Astrophysics · Physics 2008-12-18 D. F. Mota , J. R. Kristiansen , T. Koivisto , N. E. Groeneboom

We show that the observed rotation curves of spiral galaxies constrain the sound speed of the dark matter to be $c_s < 10^{-4} c$, where $c$ is the speed of light in vacuum. Using the Modified Chaplygin Gas as a representative example of a…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-06 P. P. Avelino , V. M. C. Ferreira