Black holes as particle detectors

Jun 18, 2012 By Florian Aigner
Artist's impression of a black hole, surrounded by axions.

(Phys.org) -- Previously undiscovered particles could be detected as they accumulate around black holes say Scientists at the Vienna University of Technology.

Finding new usually requires high energies – that is why huge accelerators have been built, which can accelerate particles to almost the speed of light. But there are other creative ways of finding new particles: At the Vienna University of Technology, scientists presented a method to prove the existence of hypothetical “axions”. These axions could accumulate around a black hole and extract energy from it. This process could emit , which could then be measured.

Axions  are hypothetical particles with a very low mass. According to Einstein, mass is directly related to energy, and therefore very little energy is required to produce axions. “The existence of axions is not proven, but it is considered to be quite likely”, says Daniel Grumiller. Together with Gabriela Mocanu he calculated at the Vienna University of Technology (Institute for Theoretical Physics), how axions could be detected.

Astronomically Large Particles

In quantum physics, every particle is described as a wave. The wavelength corresponds to the particle’s energy. Heavy particles have small wavelengths, but the low-energy axions can have wavelengths of many kilometers. The results of Grumiller and Mocanu, based on works by Asmina Arvanitaki and Sergei Dubovsky (USA/Russia), show that axions can circle a black hole, similar to electrons circling the nucleus of an atom. Instead of the electromagnetic force, which ties the electrons and the nucleus together, it is the gravitational force which acts between the axions and the black hole.

The Boson-Cloud

However, there is a very important difference between electrons in an atom and axions around a black hole: Electrons are fermions – which means that two of them can never be in the same state. Axions on the other hand are bosons, many of them can occupy the same quantum state at the same time. They can create a “boson-cloud” surrounding the black hole. This cloud continuously sucks from the black hole and the number of axions in the cloud increases.

Sudden Collapse

Such a cloud is not necessarily stable. “Just like a loose pile of sand, which can suddenly slide, triggered by one single additional grain of sand, this boson cloud can suddenly collapse”, says Daniel Grumiller. The exciting thing about such a collapse is that this “bose-nova” could be measured. This event would make space and time vibrate and emit gravity waves. Detectors for gravity waves have already been developed, in 2016 they are expected to reach an accuracy at which gravity waves should be unambiguously detected. The new calculations in Vienna show that these gravity waves can not only provide us with new insights about astronomy, they can also tell us more about new kinds of particles.

Explore further: Researchers demonstrate ultra low-field nuclear magnetic resonance using Earth's magnetic field

More information: Original publication: prd.aps.org/abstract/PRD/v85/i10/e105022
free arxiv-version: arxiv.org/abs/arXiv:1203.4681

Additional information, written by Gabriela Mocanu: www.tuwien.ac.at/fileadmin/t/t… s/pa/black_holes.pdf

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User comments : 20

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Noumenon
2.4 / 5 (28) Jun 18, 2012
hmmm, yes, yes!,... since gravity waves are hypothetical, ...it makes sense to detect them with hypothetical particles,.... hypothetically speaking of course (j/k).
chardo137
not rated yet Jun 18, 2012
Black holes have mass, angular momentum, and electric charge. Is this suggesting that axion number needs to be added to the list of properties that it is possible for black holes to have? Black holes have no hair, but possibly they do have axions?
Noumenon
2 / 5 (24) Jun 18, 2012
Axions are external to BH's.
Phil DePayne
2.3 / 5 (3) Jun 18, 2012
A simpler way to produce axions would be with a tabletop particle accelerator, perhaps driven by negative mass-energy. BTW, I have a spare warp drive I'm gonna post on eBay, come check it out.
Torbjorn_Larsson_OM
5 / 5 (1) Jun 18, 2012
@ Noumenon: But the experiment would detect and establish gravity waves first, from other sources as well.

Using two theories for an unambiguous detection is no worse than using an experiment in the first place, seeing how it must be adapted to make the observation. Sometimes you use the theory you test to make the adaptation. (Say, when adjusting light intensity for optical experiments.)
Torbjorn_Larsson_OM
5 / 5 (1) Jun 18, 2012
@ Phil: I'll teleport over any day, if you give me a first buy option.

[Relative negative mass-energy would be dark energy and similar large scale pressures in GR, right? Analogous to relative negative potential energy. Don't think you can make a tabletop of the first... The latter would be easy, just placing the accelerator on the table-top. =D]
Phil DePayne
not rated yet Jun 18, 2012
Of course, torbjorn... I was just making sure you were paying attention
Noumenon
2 / 5 (24) Jun 18, 2012
@ Noumenon: But the experiment would detect and establish gravity waves first, from other sources as well.

Using two theories for an unambiguous detection is no worse than using an experiment in the first place, seeing how it must be adapted to make the observation. Sometimes you use the theory you test to make the adaptation. (Say, when adjusting light intensity for optical experiments.)


(j/k) = "just kidding"
searchingbeyondboundaries
not rated yet Jun 18, 2012
" These axions could accumulate around a black hole and extract energy from it. This process could emit gravity waves, which could then be measured."
Will anybody explain how (or, with what instrument) can these "gravity wave" signatures be observed and "measured", which would in turn help detecting axions?
dschlink
5 / 5 (1) Jun 18, 2012
There are many approaches to building a GW detector. Granted none of them have achieved sufficient sensitivity to actually detect anything less than a couple large black holes merging. But, eventually we will either detect them or eliminate the possibility. Either would be interesting.

http://en.wikiped...detector
vacuum-mechanics
1 / 5 (3) Jun 19, 2012
The paper say This event would make space and time vibrate and emit gravity waves.

By the way, it is interesting to note that according to theory of relativity, space is not a physical thing with mechanical property, then how could it vibrate and emit gravity waves! May be this unconventional view could give some hint.
http://www.vacuum...mid=7=en
CardacianNeverid
2 / 5 (4) Jun 19, 2012
By the way, it is interesting to note that according to theory of relativity, space is not a physical thing with mechanical property, then how could it vibrate and emit gravity waves! -VacuumHead

Give a reference in GR where it states that space is not a physical thing.
Graeme
not rated yet Jun 19, 2012
A similar kind of effect could happen with neutrinos. At low energy they have a large wavelength too. However being fermions will not be able to accumulate to arbitrary densities. But when an axion or neutrino fall near a blackhole they will be moving fast, and the wavelength will be small. If axions form a kind of furball in a gravity well, then you should also be able to find them at the centre of the earth as well.
TkClick
1 / 5 (5) Jun 19, 2012
Black holes have no hair, but possibly they do have axions?
We never observed both the black holes, both the axions.
This cloud continuously sucks energy from the black hole and the number of axions in the cloud increases.
It would violate the definition of black hole, in which no energy can escape from black hole. But it's not so distant from my assumption, that the black hole can emanate neutrinos. It would require the superluminal neutrino speed, mediated with axions, sterile neutrinos (which I do consider equivalent to axions phenomenologically) or whatever else.
TkClick
1 / 5 (5) Jun 19, 2012
I speculated here before some time, the neutrinos are behaving like the chiral vortex rings, which change helicity periodically. In a brief moment of time the neutrino will change to the neutral vortex ring, i.e. the sterile or Majorana neutrino. Because such a neutrino is essentially a graviton only, it should propagate with superluminal speed like the gravitational wave and it could escape from black hole in such way. The above theory points to the similar outcome. We should realize, that the theories are mutually connected: if we allow the violation of black hole properties defined with relativity, then the relativity must be violated too. Note that steady state model of Universe requires some mechanism for evaporation of black holes, or the universe would be filled with black holes already. Now the question is, if the energy can be released from black holes in bosenova explosions only, or whether it could be released continually in form of polar jets. I do support the 2nd option.
TkClick
1 / 5 (4) Jun 19, 2012
Unfortunately the last OPERA finding were rather dismissive regarding the superluminal neutrino speed. The hope remains in MINOS experiment (which still didn't exclude the superluminal neutrino observation from 2007) and in comparison of photon and neutrino arrival times during remote gamma ray bursts and supernova flares. It could be pointed out, that the bosenova explosions may be actually responsible for somewhat mysterious explosions of the black hole at the center of Milky Way, which I presume could be responsible for gamma ray lobes and global warming period which we experience by now. The axion theory could therefore have quite tangible impact for human civilization.
TkClick
Jun 19, 2012
This comment has been removed by a moderator.
TkClick
1 / 5 (2) Jun 26, 2012
This galaxy NGC-1097 does what I'm looking for and what maybe the whole article is about: the neutrino jets.. You just can't see it, because neutrinos cannot be seen..
yyz
5 / 5 (2) Jun 26, 2012
"This galaxy NGC-1097 does what I'm looking for and what maybe the whole article is about: the neutrino jets.. "

While NGC 1097 may appear to show multiple jets from a central supermassive black hole, appearances can be (and in this case are) deceiving.

Multiwavelength studies of NGC 1097 have revealed the "jets" are actually stellar tidal streams from a small dwarf galaxy being cannabalized by the larger galaxy. The viewing angle of the stellar streams from Earth gives the appearance of jets in this system. The streams are similar in nature to those found around several nearby galaxies, e.g. NGC 5907: http://apod.nasa....619.html

Details of the stellar nature of the "jets" in NGC 1097 can be found here:

http://arxiv.org/abs/1006.1353
http://iopscience...85/1/281

So it would appear NGC 1097 displays no jet activity at all (neutrino or otherwise)!
TkClick
not rated yet Jun 26, 2012
Nope - I'm talking about jets of NGC 1097, not about some streams of NGC 5907... The streams are curved and the probability we would see all streams straight from single viewing angle is pretty low - don't you think?
yyz
5 / 5 (1) Jun 26, 2012
But we don't see the streams in NGC 1097 as "straight". Jet 2 in your image shows the so-called "dog-leg" feature where the stream abruptly bends nearly 90 degrees. Stream 2 also displays a gentle S-curve just before the dog-leg, centered on the suspected progenitor galaxy for the stream, knot A. Figure 8 in my first ref has a good view of this distortion in Jet 2.

Additionally, as far back as 1976 it has been known that Jets 1 & 3 and Jets 2 & 4 "are not precisely linear structures but slightly curved"(see my second ref). And if the jets were being emitted by a central SMBH, there should be evidence for synchrotron or bremsstrahlung emission. The SED of the jets is inconsistent with both.

There are multiple lines of evidence that the streams are stellar in nature and result from tidal disruption of a dwarf galaxy....please see the refs I have included. As for the apparent X-shape of the "jets", my second ref includes a model that reproduces the observed geometry(incl the dog-leg).