Abstract Motivated by the recent heated debate on whether masses of local objects, such as compact stars or black holes (BHs), may be affected large-scale, cosmological dynamics, we analyze conditions under which, in a general relativity framework, coupling small/large scales is allowed. We shed light some controversial arguments, which have been used to rule out latter possibility. find that occurs whenever energy central objects quantified quasi-local Misner-Sharp mass (MS). Conversely,...

Abstract We show that — in the framework of general relativity (GR) if black holes (BHs) are singularity-free objects, they couple to large-scale cosmological dynamics. find leading contribution resulting growth BH mass ( M ) as a function scale factor stems from curvature term, yielding ∝ k , with = 1. demonstrate such linear scaling is universal for spherically-symmetric and it only case regular BHs. For nonsingular horizonless compact objects we instead obtain an additional subleading...

Abstract We investigate the cosmological coupling of spherical, local astrophysical systems. derive a general formula quantifying Misner-Sharp mass these objects. show that, in weak-field limit, is only allowed if there are pressure anisotropies. also apply our results to galaxies, modelling them with Navarro-Frenk-White and Einasto profiles. that galactic can be coupled dynamics examine its dependence on scale factor universe.

We revisit Hawking's original derivation of the evaporation process in a non-stationary spacetime, presenting it clear and pedagogical manner, with focus on spherical collapse star into black hole. Our analysis highlights underlying assumptions calculations, clarifying their physical significance, potential implications, limitations this approach.

Abstract We present exact solutions for the cosmological embedding of a broad class non-singular black holes and we focus on behavior their apparent horizons. The evolution latter is analyzed as function redshift z . show that its size exceeds event horizon an isolated hole increases monotonically with increasing Explicit formulas numerical results are provided specific cases Hayward Fan & Wang black-hole models. Furthermore, explore distinct dynamical roles horizons, highlighting...

Abstract We show that, in the framework of Einstein-scalar gravity, gravitational coupling can drive nucleation de Sitter (dS) spacetime from an anti (AdS) one. This is done using a static and spherically-symmetric metastable scalar lump solution. features $$\text {AdS}_4$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mtext>AdS</mml:mtext> <mml:mn>4</mml:mn> </mml:msub> </mml:math> solution’s core, allows for {dS}_4$$ <mml:mtext>dS</mml:mtext> vacua plagued by...

We explore the possibility of embedding regular compact objects with an (anti-)de Sitter [(A)dS] core as solutions Einstein's gravity minimally coupled to a real scalar field. consider, among others, interpolating between inner, potential-dominated and outer, kinetic-term-dominated region. Owing their analogy slow-roll inflation, we term them gravitational vacuum inflative stars, or gravistars for short. systematically discuss approximate theory describing either asymptotically flat region...

We show that -- in the framework of general relativity (GR) if black holes (BHs) are singularity-free objects, they couple to large-scale cosmological dynamics. find leading contribution resulting growth BH mass ($M_{\rm BH}$) as a function scale factor $a$ stems from curvature term, yielding $M_{\rm BH} \propto a^k$, with $k=1$. demonstrate such linear scaling is universal for spherically-symmetric and it only case regular BHs. For nonsingular horizonless compact objects we instead obtain...

Motivated by the recent heated debate on whether masses of local objects, such as compact stars or black holes (BHs), may be affected large-scale, cosmological dynamics, we analyze conditions under which, in a general relativity framework, coupling small/large scales is allowed. We shed light some controversial arguments, which have been used to rule out latter possibility. argue that actual observational quantity at play quasi-local Misner-Sharp mass (MS), and find occurs whenever energy...

We investigate the cosmological coupling of spherical, local astrophysical systems. derive a general formula quantifying Misner-Sharp mass these objects. show that, in weak-field limit, is only allowed if there are pressure anisotropies. also apply our results to galaxies, modelling them with Navarro-Frenk-White and Einasto profiles. that galactic can be coupled dynamics examine its dependence on scale factor universe.

We show that, in the framework of Einstein-scalar gravity, de Sitter (dS) spacetime can be nucleated out anti (AdS) one. This is done by using a scalar lump solution, which has an $\text{AdS}_4$ core, allows for $\text{dS}_4$ vacua and was found to plagued tachyonic instabilities. Using Euclidean action formalism, we compute compare probability amplitudes free energies vacua. Our results that former generally less favored than latter, with most preferred state being vacuum. The lump, thus,...

We present exact solutions for the cosmological embedding of a broad class non-singular black holes, demonstrating that these objects exhibit an apparent horizon. The evolution latter is analyzed as function redshift $z$. show its size exceeds event horizon isolated hole and increases monotonically with increasing Explicit formulas numerical results are provided specific cases Hayward Fan $\&$ Wang black-hole models. Furthermore, we explore distinct dynamical roles horizons, highlighting...

Using the Functional Renormalization Group approach we construct effective quantum spacetime geometries by self-consistently deforming classical Schwarzschild-de Sitter black-hole solution. This involves studying how corrections, driven running of Newton's and cosmological constants modify solution across infrared ultraviolet regimes. We show that these modifications replace Schwarzschild singularity with a milder conical one. Moreover, two new features emerge in regime. First, identify...

We explore the possibility of embedding regular compact objects with (anti) de Sitter ((A)dS) core as solutions Einstein's gravity minimally coupled to a real scalar field. consider, among others, interpolating between an inner, potential-dominated and outer, kinetic-term-dominated region. Owing their analogy slow-roll inflation, we term them gravitational vacuum inflative stars, or gravistars for short. systematically discuss approximate theory describing either asymptotically-flat region...