Quadratic Rastall gravity: from low-mass HESS J1731−347 to high-mass PSR J0952−0607 pulsars
- Resource Type
- article
- Authors
- Waleed El Hanafy
- Source
- European Physical Journal C: Particles and Fields, Vol 84, Iss 4, Pp 1-22 (2024)
- Subject
- Astrophysics
QB460-466
Nuclear and particle physics. Atomic energy. Radioactivity
QC770-798
- Language
- English
- ISSN
- 1434-6052
Abstract Similar to Rastall gravity we introduce matter-geometry nonminimal coupling which is proportional to the gradient of quadratic curvature invariants. Those are mimicking the conformal trace anomaly when backreaction of the quantum fields to a curved spacetime geometry is considered. We consider a static spherically symmetric stellar structure with anisotropic fluid and Krori-Barua metric potentials model to examine the theory. Confronting the model with NICER + XMM-Newton observational constraints on the pulsar PSR J0740 $$+$$ + 6620 quantifies the amount of the nonminimal coupling via a dimensionless parameter $$\epsilon \simeq -0.01$$ ϵ ≃ - 0.01 . We verify that the conformal symmetry is broken everywhere inside the pulsar as the trace anomaly $$\varDelta >0$$ Δ > 0 , or equivalently the trace of the stress-energy tensor $${\mathfrak {T}}