Possible observational windows for quantum effects from black holes

Giddings, Steven B.

doi:10.1103/physrevd.90.124033

Cited by 91 publications

(98 citation statements)

References 71 publications

(162 reference statements)

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“…Such "primordial black holes" may even contribute to the dark matter in the Universe (Blais et al, 2002) and produce gravitational waves (Bird et al, 2016). Second, according to recent speculations, quantum effects may potentially become relevant near the horizon of a macroscopic black hole; for example, in the form of a "firewall" (Calmet, 2015); see also Giddings (2014). It is an intriguing question whether such effects, if present, could be observed with the EHT.…”

Section: Black Holes and Quantum Theorymentioning

confidence: 99%

The Milky Way’s Supermassive Black Hole: How Good a Case Is It?

Eckart

Hüttemann²,

Kiefer³

et al. 2017

Found Phys

122

105

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The compact and, with 4.3±0.3×106 M ⊙ , very massive object located at the center of the Milky Way is currently the very best candidate for a supermassive black hole (SMBH) in our immediate vicinity. The strongest evidence for this is provided by measurements of stellar orbits, variable X-ray emission, and strongly variable polarized near-infrared emission from the location of the radio source Sagittarius A* (SgrA*) in the middle of the central stellar cluster. Simultaneous near-infrared and X-ray observations of SgrA* have revealed insights into the emission mechanisms responsible for the powerful near-infrared and X-ray flares from within a few tens to one hundred Schwarzschild radii of such a putative SMBH at the center of the Milky Way. If SgrA* is indeed a SMBH it will, in projection onto the sky, have the largest event horizon and will certainly be the first and most important target of the Event Horizon Telescope (EHT) Very Long Baseline Interferometry (VLBI) observations currently being prepared. These observations in combination with the infrared interferometry experiment GRAVITY at the Very Large Telescope Interferometer (VLTI) and other experiments across the electromagnetic spectrum might yield proof for the presence of a black hole at the center of the Milky Way. The large body of evidence continues to discriminate the identification of SgrA* as a SMBH from alternative possibilities. It is, however, unclear when the ever mounting evidence for SgrA* being associated with a SMBH will suffice as a convincing proof. Additional compelling evidence may come from future gravitational wave observatories. This manuscript reviews the observational facts, theoretical grounds and conceptual aspects for the case of SgrA* being a black hole. We treat theory and observations in the framework of the philosophical discussions about "(Anti)Realism and Underdetermination", as this line of arguments allows us to describe the situation in observational astrophysics with respect to supermassive black holes. Questions concerning the existence of supermassive black holes and in particular SgrA* are discussed using causation as an indispensable element. We show that the results of our investigation are convincingly mapped out by this combination of concepts.

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Section: Black Holes and Quantum Theorymentioning

confidence: 99%

The Milky Way’s Supermassive Black Hole: How Good a Case Is It?

Eckart

Hüttemann²,

Kiefer³

et al. 2017

Found Phys

122

105

View full text Add to dashboard Cite

show abstract

“…Giddings, in particular, has observed that the possibility that such quantum gravity effects could lead to observable effects cannot be completely excluded, and listed a number of such possibilities in [14]. For instance, quantum gravitational fluctuations of the metric could disrupt the accretion flow in the near-horizon atmosphere region, distort or suppress the photon ring [16], or distort the edge of the shadow [17].…”

mentioning

confidence: 99%

“…Examples are the quantum description of black holes as Bose-Einstein condensates [4,5], fuzzbals [6], Planck star tunnelling [7][8][9][10][11][12][13], and Giddings's metric fluctuations [14]. Also, one possible interpretation of the firewall theorem [15], which has recently raised a lively discussion in the theoretical world, is as an indication that "something strange" should have to happen at the horizon of a macroscopic black hole, possibly violating the hypotheses of the theorem, which include the validity of local quantum field theory on a given background geometry.…”

mentioning

confidence: 99%

Quantum gravity effects around Sagittarius A*

Haggard

Rovelli

2016

Int. J. Mod. Phys. D

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Recent VLBI observations have resolved Sagittarius A* at horizon scales. The Event HorizonTelescope is expected to provide increasingly good images of the region around the Schwarzschild radius r S of Sgr A* soon. A number of authors have recently pointed out the possibility that nonperturbative quantum gravitational phenomena could affect the space surrounding a black hole.Here we point out that the existence of a region around 7 6 r S where these effects should be maximal.

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“…In the framework of standard physics, the spacetime geometry around these objects should be described by the Kerr solution of general relativity. However, an observational confirmation is still lacking and deviations from standard predictions can be motivated by a number of arguments, from classical extensions of general relativity [2][3][4][5] to macroscopic quantum effects [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Shadows of CPR black holes and tests of the Kerr metric

Ghasemi-Nodehi

Bambi

2015

Eur. Phys. J. C

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We study the shadow of the Cardoso-Pani-Rico black hole for different values of the black hole spin a * , the deformation parameters t 3 and r 3 , and the viewing angle i. We find that the main impact of the deformation parameter t 3 is the change of the size of the shadow, while the deformation parameter r 3 affects the shape of its boundary. In general, it is impossible to test the Kerr metric, because the shadow of a Kerr black hole can be reproduced quite well by a black hole with non-vanishing t 3 or r 3 . Deviations from the Kerr geometry could be constrained in the presence of high quality data and in the favorable case of a black hole with high values of a * and i. However, the shadows of some black holes with non-vanishing r 3 present peculiar features and the possible detection of these shadows could unambiguously distinguish these objects from the standard Kerr black holes of general relativity.

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Possible observational windows for quantum effects from black holes

Cited by 91 publications

References 71 publications

The Milky Way’s Supermassive Black Hole: How Good a Case Is It?

The Milky Way’s Supermassive Black Hole: How Good a Case Is It?

Quantum gravity effects around Sagittarius A*

Shadows of CPR black holes and tests of the Kerr metric

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