Slowly rotating gravastars

Beltracchi, Philip; Gondolo, Paolo; Mottola, Emil

doi:10.1103/physrevd.105.024002

Cited by 21 publications

(34 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Buchdhal's theorem assumes that matter is described by a perfect fluid, and can be extended to mildly anisotropic fluids for which the radial pressure is larger than the tangential one [14] (see [16,17] for more general results). Indeed, compact objects made of strongly anisotropic fluids (e.g., gravastars [18] and anisotropic stars [19]) can have higher compactness and a continuous BH limit, M=R → 1=2 [20][21][22][23]. However, the viability of such ultracompact models is questionable, since they either violate some of the energy conditions [24] or feature superluminal speed of sound or ad hoc thin shells within the fluid (see [12] for a discussion).…”

Section: Introductionmentioning

confidence: 99%

Compact elastic objects in general relativity

et al. 2022

View full text Add to dashboard Cite

We introduce a rigorous and general framework to study systematically self-gravitating elastic materials within general relativity, and apply it to investigate the existence and viability, including radial stability, of spherically symmetric elastic stars. We present the mass-radius (M − R) diagram for various families of models, showing that elasticity contributes to increasing the maximum mass and the compactness up to ≈22%, thus supporting compact stars with mass well above two solar masses. Some of these elastic stars can reach compactness as high as GM=ðc 2 RÞ ≈ 0.35 while remaining stable under radial perturbations and satisfying all energy conditions and subluminal wave propagation, thus being physically realizable models of stars with a light ring. We provide numerical evidence that radial instability occurs for central densities larger than that corresponding to the maximum mass, as in the perfect-fluid case. Elasticity may be a key ingredient to building consistent models of exotic ultracompact objects and black hole mimickers, and can also be relevant for a more accurate modeling of the interior of neutron stars.

show abstract

Section: Introductionmentioning

confidence: 99%

Compact elastic objects in general relativity

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Effects of rotational angular momentum have also been neglected in the simplest gravastar solution, although the first steps in including those effects have been taken in [37,38]. The EFT solutions of static or stationary gravastars also leaves unexamined the process of their formation, and in particular the behavior of the stress tensor near the would-be horizon of collapsing matter, which would have to activate the dynamical condensate terms of (8.1)-(8.12).…”

Section: Discussion and Outlook: Vacuum Energy As A Dynamical Condensatementioning

confidence: 99%

“…The localized formation of such a p = −ρ gravitational vacuum condensate within an ultra compact star can occur only if there at least one additional degree of freedom in the low energy EFT of gravity, whose variation allows Λ eff to change abruptly at or near r = r M . This turns the BH horizon from a mathematical surface to a physical phase boundary layer with a positive surface tension [36][37][38].…”

Section: The Quantum Vacuum and Vacuum Energy In Black Holes And Cosm...mentioning

confidence: 99%

The Effective Theory of Gravity and Dynamical Vacuum Energy

Mottola

2022

Preprint

Self Cite

View full text Add to dashboard Cite

Gravity and general relativity are considered as an Effective Field Theory (EFT) at low energies and macroscopic distance scales. The effective action of the conformal trace anomaly of light or massless quantum fields has significant effects on macroscopic scales, owing to its describing light cone singularities not captured by an expansion in local curvature invariants. A compact local form for the Wess-Zumino effective action of the conformal anomaly and stress tensor is given, involving the introduction of a new light scalar, which it is argued should be included in the low energy effective action for gravity. This scalar conformalon couples to the conformal part of the spacetime metric and allows the effective value of the vacuum energy, described as a condensate of a 4-form abelian gauge field, to change in space and time. The EFT of vacuum energy thereby replaces the fixed constant Λ of the classical theory with a dynamical condensate whose natural ground state value in empty flat space is Λ eff = 0 identically. In addition to the conformal anomaly, the principal physical inputs to the EFT are a topological vacuum susceptibility characterizing the coupling of the 4-form condensate to the anomaly current, in analogy to the chiral susceptibility of QCD, and the extension of the fermion anomaly to a general Einstein-Cartan space including torsion. By allowing Λ eff to vary rapidly near a black hole horizon, the EFT of dynamical vacuum energy provides an effective Lagrangian framework for gravitational condenstate stars, as the final state of complete gravitational collapse consistent with quantum theory. The possible consequences of dynamical vacuum dark energy in cosmology, the cosmic coincidence problem, and the role of conformal invariance for other fine tuning issues in the Standard Model are discussed.

show abstract

“…However constraints based on accretion models are model dependent, and have also been Snowmass2021 Cosmic Frontier White Paper questioned [227]. They still leave open the possibility of a surface close to the wouldbe event horizon, as predicted in thin shell gravastar models [173,174,228,229]. The planned EHT and future surveys of tidal disruption events will improve current constraints on the location of a hypothetical surface by two orders of magnitude.…”

Section: Testing the Existence Of Horizonsmentioning

confidence: 99%

Snowmass2021 Cosmic Frontier White Paper: Fundamental Physics and Beyond the Standard Model

Berti¹,

Cardoso²,

Haiman³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

Gravitational wave detectors are formidable tools to explore strong-field gravity, especially black holes and neutron stars. These compact objects are extraordinarily efficient at producing electromagnetic and gravitational radiation. As such, they are ideal laboratories for fundamental physics and have an immense discovery potential. The detection of black hole binaries by third-generation Earth-based detectors, space-based detectors and pulsar timing arrays will provide exquisite tests of general relativity. Loud "golden" events and extreme mass-ratio inspirals can strengthen the observational evidence for horizons by mapping the exterior spacetime geometry, inform us on possible near-horizon modifications, and perhaps reveal a breakdown of Einstein's gravity. Measurements of the black-hole spin distribution and continuous gravitational-wave searches can turn black holes into efficient detectors of ultralight bosons across ten or more orders of magnitude in mass. A precise monitoring of the phase of inspiralling binaries can constrain the existence of additional propagating fields and characterize the environment in which the binaries live, bounding the local dark matter density and properties. Gravitational waves from compact binaries will probe general relativity and fundamental physics in previously inaccessible regimes, and allow us to address fundamental issues in our current understanding of the cosmos.

show abstract

Slowly rotating gravastars

Cited by 21 publications

References 61 publications

Compact elastic objects in general relativity

Compact elastic objects in general relativity

The Effective Theory of Gravity and Dynamical Vacuum Energy

Snowmass2021 Cosmic Frontier White Paper: Fundamental Physics and Beyond the Standard Model

Contact Info

Product

Resources

About