Do we need dense matter equation of state in curved spacetime for neutron stars?

Abstract

Neutron stars are regarded as natural laboratories for the study of dense strong interaction matter. The equation of state (EoS) of dense matter computed in flat spacetime is used to predict the structure of neutron stars by solving the Tolman-Oppenheimer-Volkoff (TOV) equation. Recently, it has been reported that the curved spacetime effect or specifically gravitational time dilation effect on the EoS of dense matter leads to a significant increase of the maximum mass limit of neutron stars [Phys. Rev. D \textbf{104}, 123005 (2021) and J. Cosmol. Astropart. Phys. 02 (2021) 026]. However, in this work, we show that to study the hydrostatic equilibrium of dense matter within the framework of general relativity and relativistic fluid dynamics, the grand canonical EoS of dense matter, $p(T,\mu )$, should be the same as that computed in flat spacetime, otherwise it is not consistent with local thermodynamic relations and energy-momentum conservation of the fluid. The gravitation influences the pressure $p$ only through enhancing the temperature $T$ and the chemical potential $\mu$, known as Tolman's law and Klein's law. We rewrite the TOV equation as an alternative version so that the grand canonical EoS computed by using field theoretical methods can be used as a direct input. This may provide a tool to study the grand canonical EoS of dense matter via deep learning.

arXiv comment9 pages, 4 figures; published version

References in corpus (18)

• The high-precision, charge-dependent Bonn nucleon-nucleon potential (CD-Bonn)
• Relativistic Shapiro delay measurements of an extremely massive millisecond pulsar
• Refined Mass and Geometric Measurements of the High-Mass PSR J0740+6620
• Using gravitational-wave observations and quasi-universal relations to constrain the maximum mass of neutron stars
• Evidence for quark-matter cores in massive neutron stars
• A Common Explosion Mechanism for Type Ia Supernovae
• Hyperon stars in the Brueckner-Bethe-Goldstone theory
• Hadron-Quark Crossover and Massive Hybrid Stars with Strangeness
• Was GW190814 a black hole -- strange quark star system?
• Large-mass neutron stars with hyperonization
• Extensive Studies of the Neutron Star Equation of State from the Deep Learning Inference with the Observational Data Augmentation
• Hyperon Puzzle, Hadron-Quark Crossover and Massive Neutron Stars
• The Hyperon Puzzle in Neutron Stars
• Neural network reconstruction of the dense matter equation of state from neutron star observables
• Thermodynamic Equilibrium in General Relativity
• Higher mass limits of neutron stars from the equation of states in curved spacetime
• Equation of states in the curved spacetime of spherical degenerate stars
• Local temperature in general relativity

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