Do unbounded bubbles ultimately become fenced inside a black hole?

Guzmán, F. S.; Lehner, Luis; Sarbach, Olivier

doi:10.1103/physrevd.76.066003

Cited by 5 publications

(9 citation statements)

References 16 publications

(35 reference statements)

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“…A small amount of artificial dissipation is added for convenience (for stabilility and convergence as well as for ensuring spurious high frequency behavior does not affect low frequency physics). For further details see [177][178][179]. Finally, in our simulations where we typically employ R = 10 −3 , 10 −2 , the timestep spacing is chosen as dt = 10 −1 dx to satisfy the Courant-Friedrichs-Levy (CFL) condition and accurately capture the rapid time-scale variations of the field dynamics.…”

Section: Methodsmentioning

confidence: 99%

Large-misalignment mechanism for the formation of compact axion structures: Signatures from the QCD axion to fuzzy dark matter

et al. 2020

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Axions are some of the best motivated particles beyond the Standard Model. We show how the attractive self-interactions of dark matter (DM) axions over a broad range of masses, from 10 −22 eV to 10 7 GeV, can lead to nongravitational growth of density fluctuations and the formation of bound objects. This structure formation enhancement is driven by parametric resonance when the initial field misalignment is large, and it affects axion density perturbations on length scales of order the Hubble horizon when the axion field starts oscillating, deep inside the radiation-dominated era. This effect can turn an otherwise nearly scale-invariant spectrum of adiabatic perturbations into one that has a spike at the aforementioned scales, producing objects ranging from dense DM halos to scalar-field configurations such as solitons and oscillons. We call this class of cosmological scenarios for axion DM production "the large-misalignment mechanism."We explore observational consequences of this mechanism for axions with masses up to 10 eV. For axions heavier than 10 −5 eV, the compact axion halos are numerous enough to significantly impact Earth-bound direct detection experiments, yielding intermittent but coherent signals with repetition rates exceeding one per decade and crossing times less than a day. These episodic increases in the axion density and kinematic coherence suggest new approaches for axion DM searches, including for the QCD axion. Dense structures made up of axions from 10 −22 eV to 10 −5 eV are detectable through gravitational lensing searches, and their gravitational interactions can also perturb baryonic structures and alter star formation. At very high misalignment amplitudes, the axion field can undergo self-interaction-induced implosions long before matter-radiation equality, producing potentially-detectable low-frequency stochastic gravitational waves.

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Section: Methodsmentioning

confidence: 99%

Large-misalignment mechanism for the formation of compact axion structures: Signatures from the QCD axion to fuzzy dark matter

et al. 2020

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“…The external boundary ideally has to be located at spatial infinit , which can be achieved with a compactifie radial coordinate (see, e.g., [14]). More commonly, the external boundary can be set far from the horizon using a logarithmic radial coordinate [15], or other sorts of stretched coordinates (e.g., [16]). In general, there is no prescription for a location of the external boundary, but it is always desirable to defin it as far away from the strong fiel region as possible, so that there the space-time is a small perturbation of Minkowski space-time.…”

Section: Numerical Solutionmentioning

confidence: 99%

“…Evolution and constraint Eqs. (33,34,35,36) involve the following geometric quantities of the hypersurfaces Σ t , Ricci scalar R, extrinsic curvature components K ij , and its trace K.…”

Section: The Non-linear Casementioning

confidence: 99%

Spherical accretion of a perfect fluid onto a black hole

Murillo¹,

Ríos²,

Amezcua³

et al. 2021

Rev. Mex. Fis. E

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In this academic paper we present in detail the numerical solution of the accretion of a perfect fluid onto a black hole. The conditions are very simple, we consider a radial flux being accreted by a Schwarzschild black hole. We present two scenarios: 1) the test field case in which the fluid does not affect the geometry of the black hole space-time background, and 2) the full non-linear scenario, in which the geometry of the space-time evolves simultaneously with the fluid according to Einstein's equations. In the two scenarios we describe the black hole space-time in horizon penetrating coordinates, so that it is possible to visualize that accretion actually takes place within the numerical domain. For the evolution of matter we use the Valencia formulation of relativistic fluid dynamics. In the non-linear scenario we solve the equations of geometry using the ADM formulation of General Relativity, with very simple and intuitive gauge and boundary conditions, and include diagnostics related to the Apparent Horizon and Event Horizon growth. In view of the recent spectacular discoveries by the Event Horizon Telescope collaboration and further discoveries to come, the aim of this paper is to provide the necessary tools for interested graduate students in Black Hole Astrophysics, to enter into the accretion modeling starting from a considerable advanced starting point.

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“…[55] for binary black hole simulations and Refs. [67,68] for the simulation of bubble spacetimes in five-dimensional theories of gravity. In particular, Refs.…”

Section: E Applications To Numerical Relativitymentioning

confidence: 99%

Absorbing boundary conditions for Einstein's field equations

Sarbach

2007

J. Phys.: Conf. Ser.

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A common approach for the numerical simulation of wave propagation on a spatially unbounded domain is to truncate the domain via an artificial boundary, thus forming a finite computational domain with an outer boundary. Absorbing boundary conditions must then be specified at the boundary such that the resulting initial-boundary value problem is well posed and such that the amount of spurious reflection is minimized. In this article, we review recent results on the construction of absorbing boundary conditions in General Relativity and their application to numerical relativity.

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Do unbounded bubbles ultimately become fenced inside a black hole?

Abstract: We examine the dynamical behavior of recently introduced bubbles in asymptotically flat, fivedimensional spacetimes. Using numerical methods, we find that even bubbles that initially start expanding eventually collapse to a Schwarzschild-Tangherlini black hole.

Cited by 5 publications

References 16 publications

Large-misalignment mechanism for the formation of compact axion structures: Signatures from the QCD axion to fuzzy dark matter

Large-misalignment mechanism for the formation of compact axion structures: Signatures from the QCD axion to fuzzy dark matter

Spherical accretion of a perfect fluid onto a black hole

Absorbing boundary conditions for Einstein's field equations

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