Friday, September 22, 2006

Micro Black Holes

Black holes are fascinating! They merge together completely different fields of physics: From General Relativity over thermodynamics and quantum field theory, they do now also reach into the regime of particle and collider physics.

As I discussed in the earlier post about extra dimension, in the presence of additional large compactified dimensions, it would be possible to produce tiny black holes at future colliders. In this case, we would be able to experimentally test Planck scale physics and the onset of quantum gravity with the Large Hadron Collider (LHC), which is scheduled to start next summer.

The formation of black holes is a fairly robust prediction and one of the most general expectations that one can have, even though the details are still subject to research.

For me, it is quite amazing to see how this field has evolved during the last decade. Starting from a smiled upon speculation, it has by now become a widely accepted scenario for physics beyond the standard model, which is included in simulations of LHC events.




1. Micro Black Holes in Large Extra Dimensions

In the standard 3+1 dimensional space-time, the production of black holes requires a concentration of energy-density which can not be reached in the laboratory. But in a higher dimensional space-time, gravity becomes stronger at small distances and therefore the event horizon is located at a larger radius. This radius can be so large that we could bring particles closer together than their horizon. A black hole could be created.

The presence of extra dimensions results in a modification of the predictions of the standard model, which become important from a certain energy scale 'the new fundamental scale', and which might be accessible at the LHC. Due to the Heisenberg uncertainty, it requires a large energy to get particles into a small volume. Only energies close by the new fundamental scale would be sufficient to produce a black hole out of this same energy.

For collider physics one is therefore interested in the case where the black hole has a mass close to the new fundamental scale. This corresponds to a horizon radius close to the inverse of the new fundamental scale, which is much much smaller than the radius of the extra dimensions. To a good approximation, this tiny black hole just does not notice that the extra dimensions are compactified, and one can neglect the boundary condition. (The higher dimensional Schwarzschild-metric for this case has been derived by Myers and Perry in '86)

On the other hand, for astrophysical objects we expect to find back the usual 3-dimensional description. In this case, the horizon radius is much larger than the radius of the extra dimensions and the influence of the extra dimensions is negligible.

Those two case are depicted in the figure below. We will be interested in the case depicted on the right side. R is the radius of the extra dimensions (all of them have the same radius) and RH is the horizon radius of the black hole.




2. Production of Black Holes

Let us consider two elementary particles, approaching each other with a very high kinetic energy in the center-of-mass system close to the new fundamental scale. At those high energies, the particles can come very close to each other since their high energy allows a tightly packed wave package despite the uncertainty relation. If the impact parameter is small enough, which will happen to a certain fraction of the particles, we have the two particles plus their large kinetic energy in a very small region of space time. If the region is smaller than the Schwarzschild radius connected with the energy of the partons, the system will collapse and form a black hole.

The production of a black hole in a high energy collision is probably the most inelastic process one might think of. Since the black hole is not an ordinary particle of the standard model, and its correct quantum theoretical treatment is unknown, it is commonly treated as a metastable state, which is produced and decays according to the semi-classical formalism of black hole physics.

To compute the production details, the cross-section of the black holes can be approximated by the classical geometric cross-section Pi R2. A common approach to improve the naive picture of colliding point particles is to treat the creation of the horizon as a collision of two shock fronts in an Aichelburg-Sexl geometry describing the fast moving particles.

Looking at the figure on the left, we also see that, due to conservation laws, the angular momentum of the formed object only vanishes in completely central collisions with zero impact parameter. In the general case, we will have an angular momentum, and the black hole might also carry an electric charge.


Another assumption which goes into the production details is the existence of a threshold for the black hole formation. From general relativistic arguments, two point like particles in a head on collision with zero impact parameter (the b in the figure above) will always form a black hole, no matter how large or small their energy. At small energies however, we expect this to be impossible due to the smearing of the wave functions by the uncertainty relation. This then results in a necessary minimal energy to allow for the required close approach. This threshold is of order of the new fundamental scale, though the exact value is unknown since quantum gravity effects should play an important role for the wave functions of the colliding particles.

Using the geometrical cross section formula, it is now possible to compute the differential and total cross sections for black hole production. This also allows us to estimate the total number of black holes, that would be created at the LHC per year. Inserting the expected technical details for the collider, one finds a number of approximately 109 created black holes per year! This means, about one black hole per second.



3. Evaporation of Black Holes

It was shown by Hawking in '75 that a black hole emits particles with a temperature that is inverse to its mass. This means, the smaller the black hole, the hotter it will be. Since we are talking about really tiny black holes, they are very hot. The typical temperature of the micro black holes is about 200 GeV or 1016 Kelvin!

The evaporation rate (massloss per time) of the higher dimensional black hole can be computed using the thermodynamics of black holes. Once produced, the black holes will undergo an evaporation process whose thermal properties carry information about the number and the radius of the extra dimension. An analysis of the evaporation will therefore offer the possibility to extract knowledge about the topology of our space time and the underlying theory.

The evaporation process can be categorized in three characteristic stages:


1. Balding phase: In this phase the black hole radiates away the multipole moments it has inherited from the initial configuration, and settles down in a hairless state. During this stage, a certain fraction of the initial mass will be lost in gravitational radiation.


2. Evaporation phase: The evaporation phase starts with a spin down phase in which the Hawking radiation carries away the angular momentum, after which it proceeds with emission of thermally distributed quanta until the black hole reaches Planck mass. The radiation spectrum contains all Standard Model particles, which are emitted on our brane, as well as gravitons, which are also emitted into the extra dimensions. It is expected that most of the initial energy is emitted in during this phase in Standard Model particles.

3. Planck phase: Once the black hole has reached a mass close to the Planck mass, it falls into the regime of quantum gravity and predictions become increasingly difficult. It is generally assumed that the black hole will either completely decay in some last few Standard Model particles or a stable remnant will be left, which carries away the remaining energy.


To perform a realistic simulation of the evaporation process, one has to take into account the various particles of the standard model with the corresponding degrees of freedom and spin statistics. In the extra dimensional scenario, standard model particles are bound too our submanifold whereas the gravitons are allowed to enter all dimensions. For a precise calculation one also has to take into account that the presence of the gravitational field will modify the radiation properties for higher angular momenta through backscattering at the potential well.

These energy dependent greybody factors can be calculated by analyzing the wave equation in the higher dimensional spacetime and the arising absorption coefficients. A very thorough description of these evaporation characteristics has been given by Kanti in 2004 which confirms the expectation that the bulk/brane evaporation rate is of comparable magnitude but the brane modes dominate.



4. Observables of Black Holes

One of the primary observables in high energetic particle collisions is the transverse momentum of the outgoing particles, pT (pee-tee), the component of the momentum transverse to the direction of the beam. Two colliding partons with high energy can produce a pair of outgoing particles, moving in opposite directions with high pT but carrying a color charge, as depicted in the figure to the right.


Due to the quark confinement, the color has to be neutralized. This results in a shower of several bound states, the hadrons, which includes mesons (consisting of a quark and an antiquark, like the pions) as well as baryons (consisting of three quarks, like the neutron or the proton). The number of these produced hadrons and their energy depends on the energy of the initial partons. This process will cause a detector signal with a large number of hadrons inside a small opening angle. Such an event is called a jet.

Typically these jets come in pairs of opposite direction. A smaller number of them can also be observed with three or more outgoing showers. This observable will be strongly influenced by the production of black holes.

To understand the signatures that are caused by the black holes we have to examine their evaporation properties. As we have seen before, the smaller the black hole, the larger is its temperature and so, the radiation of the discussed tiny black holes is the dominant signature caused by their presence. The high temperature results in a very short lifetime such that the black hole will decay close by the collision region and can be interpreted as a metastable intermediate state.

Due to the high energy captured in the black hole, the decay of such an object is a very spectacular event with a distinct signature. The number of decay products, the multiplicity, is high compared to standard model processes and the thermal properties of the black hole will yield a high sphericity of the event. Furthermore, crossing the threshold for black hole production causes a sharp cut-off for high energetic jets as those jets now end up as black holes instead, and are re-distributed into thermal particles of lower energies. Thus, black holes will give a clear signal. A schematic picture of this process is shown on the left.

It is apparent that the consequences of black hole production are quite disastrous for the future of collider physics! Once the collision energy crosses the threshold for black hole production, no further information about the structure of matter at small scales can be extracted. As it was put by Giddings and Thomas, this would be ''the end of short distance physics''.

By now, several experimental groups include black holes into their search for physics beyond the standard model. Ideally, the energy distribution of the decay products allows a determination of the temperature (by fitting the energy spectrum to the predicted shape) as well as of the total mass of the object (by summing up all energies). This then allows to reconstruct the fundamental scale, and the number of extra dimensions.

The quality of the determination depends on the uncertainties in the theoretical prediction as well as on the experimental limits e.g. background from standard model processes. Besides the formfactors of black hole production and the greybody factors of the evaporation, the largest theoretical uncertainties turnout to be the final decay and the time variation of the temperature. In case the black hole decays very fast, it can be questioned whether it has time to readjust its temperature at all or whether it essentially decays completely with its initial temperature. Also, the determination of the properties depends on the number of emitted particles. The less particles, the more difficult the analysis.

However, in my opinion the most crucial uncertainty are the latest stages of the evaporation. For hadron colliders like the LHC, the last stages with black hole masses close by the production threshold will dominate the signature, since most of the black holes are actually produced out of parton collisions with a total center-of-mass energy close by even this threshold. In hadronic collisions there are thus very little black holes which actually capture the total available energy of 14 TeV, since the proton's energy gets distributed on its constituents. Such a problem would not be present for a lepton collider.

See also:




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39 comments:

paul valletta said...

According to Penrose's latest seminar at the Perimiter Institute, dated 12th Sept 06:

http://streamer.perimeterinstitute.ca:81/mediasite/viewer/FrontEnd/Front.aspx?&shouldResize=False

(go to seminar series for the latest lecture), the Time paramiters of Blackhole creation, would invoke distortion into the observed Data?..things would be "very_messy"?

How does one differentiate Planck Time scales?

My basic understanding is the emerging Particles would not be "aware" of the experiment setup, ie particle exchange from Dimensional exchange?

Like my webpages linked, the information would be hard to untangle?...information would be lost.

I know one can make a good calculated guess from the available data, but this can also have variable consequences!

Great thread by the way B.

Count Iblis said...

If there can be heavy stable remnants left after evaporation, wouldn't these be produced in the early universe, leading to an overclosed universe?

Mahndisa S. Rigmaiden said...

09 23 06

Good post B. I did a version of this topic, but was not as thorough as you!

Bee said...

Hi Paul,

yes, that's of course right. Even though there has been lots of work invested into figuring out how black holes would form in two particle collisions, I doubt that this (classical) picture can possibly give us a realistic impression of the way the creation of a black hole happens at energy scales close by the Planck mass. Most of these investigations deal with colliding shock fronts, and in this spacetime one then searches for trapped surfaces, see e.g. the papers by Giddings and Rychkov.

However, though there might be QUANTITATIVE distortions of the above outlined simplified picture, I have little doubt that black hole creation will roughly happen the way we expect it, even close by the Planck scale. But to be honest, the reason why I don't want to be involved into all these monte-carlo event generations is exactly that there are too many unknown factors to make QUANTITATIV predictions. One of these factors being the time-dependence of the formation, another one being the late stages of the evaporation. Penrose is completely right, things are probably pretty messy.

One way or the other, the problem of information loss would be difficult to answer from the decay in a particle collision. For one, the detectors usually don't cover 4 Pi, but more importantly, the hole would also emit gravitons which do carry information, but are not detected.

Best regards,

Sabine

Bee said...

Hi Count,

brilliant question! It is brilliant because it touches the most important reason why one shouldn't expect too much from models with large extra dimensions. The processes in the early universe depend sensibly on the time-evolution of the extra dimensions, esp. why and how they are stabilized at a finite, but 'large' radius (large meaning, much larger than the Planck scale). You might also ask why and how are particles trapped to the brane, were there several branes, possibly colliding etc. But for me the question of stabilization of the compactified dimensions is the most pressing one.

The obvious answer to your question would be that the conditions of black hole formation in the early universe must be constrained such that overclosure does not happen. This sets constraints on the reheating, etc, but these constraints depend on the scenario how the extra dimensions evolve. Some of that is already discussed in the first ADD papers

Early Inflation and Cosmology in Theories with Sub-Millimeter Dimensions

Phenomenology, Astrophysics and Cosmology of Theories with Sub-Millimeter Dimensions and TeV Scale Quantum Gravity

It is possible to imagine scenarios in which the problem does not arise. In general constraints on large extra dimensions from astrophysics are pretty tight, pushing the new fundamental scale up into the range > 10 TeV, the smaller d, the higher the scale must be. This kind of disfavours the scenario. To be frank, I don't see any point in working out details of structure formation as long as we don't know why and how the dimensions are stabilized. I'd hope it would be possible to come up with a dynamical mechanism that does this, preferably one that also explains the large radii.

Best regards,

Sabine

QUASAR9 said...

The obvious answer to your question would be that the conditions of black hole formation in the early universe must be constrained such that overclosure does not happen. This sets constraints on the reheating, etc, but these constraints depend on the scenario how the extra dimensions evolve.

Hi Bee, I have been mulling over this post a couple of days.
It presents two problems for me, and let us not forget we are theorizing.
If microstate blackholes happen roughly as you expect them to ...
will these microstate blackholes be creating Smolin's parallel universes, or simply a handful of gravitons into another 'dimension' the hole would also emit gravitons which do carry information, but are not detected.

In general constraints on large extra dimensions from astrophysics are pretty tight, pushing the new fundamental scale up into the range > 10 TeV, the smaller d, the higher the scale must be. This kind of disfavours the scenario. To be frank, I don't see any point in working out details of structure formation as long as we don't know why and how the dimensions are stabilized. I'd hope it would be possible to come up with a dynamical mechanism that does this, preferably one that also explains the large radii.

See Bee, even if you create a microstate blackhole or 'bubble' with a few (handful) of gravitons,
[which I'm rather hoping JoAnne gets] these will serve to show that gravitons can and do exist in this other dimension.
But you will not have created one of Smolin's parallel worlds, unless you call a dimension a world, and a world a universe.

Collapsed (imploded or exploded)Star Blackholes are something different altogether. They are very much in our 4D (3D+T) Space.

They are not Smolin's routes to other worlds (well I won't deny the possibility that it could be the case, in some instances but not as a general rule).
They are massively (small) dense singularities which when they attract too much matter and become tooo voluminous, expand to create new Stars, solar systems and/or Galaxies.

Like the proverbial cloud, where one molecule turns it to rain, or one speck of dust lets rip a chain reaction of (volts) thunderbolts and lightning.

If you prefer "the straw that broke the camel's back"

QUASAR9 said...

And I won't even enter into whether the Planck scale is where this universe started,

Did it come into existance thru a microstate blackhole???

The microstate blackhole will not be created till after the collider collision or bigbang simulation.

Hmmm I no longer feel as hungry as a lion.
I'm starting to feel as hungry as a blackhole, but I only like the cheese and other pizza toppings. I'm not keen on the pizza base, I get bloated and expand.

CapitalistImperialistPig said...

About your hypothesized BH production rate in the LHC. Am I right that this is based on the assumption that extra dimensions are as large as they could possibly be given current experimental constraints?

QUASAR9 said...

Inside Stable wormholes(?)
levitation
Meissner effect
diamagnetism levitating frog

Bee, the levitating frog is amusing, but have you read about light in the wiki entry on levitation

Some retrospectives on LQG and ST
some distant bounding surface

Bee said...

Hi Quasar,

as always you are providing me with a surprising and new perspective :-) It's interesting to think about Smolin's baby universes when you allow allegedly intelligent lifeforms to produce black holes. Does that mean that the existence of intelligent life itself can improve the 'fitness' of its own universe?

Anyhow, as far as I know Lee doesn't have any extra dimensions in his scenario. Also - and I actually think this is a major shortcoming of CNS - the black holes don't evaporate, nor do they have other time-evolution like accretion or the like. How would that look from the inside, alias the new universe?

If you do believe in CNS and that every black hole is door to a new universe, then also the micro black holes would be such.

I don't quite understand your comment with the singularities. The point is that Lee has removed the singularities inside the black hole, this is one of the central assumptions (besides the almost-continuous and non-random choice of parameters from one generation to the next).

You see, what puzzles me is when our universe came into life through a black hole formed in another universe, then what happens if a stupid observer falls into the black hole? I think, I actually asked Lee about that at some point, he correctly said that inside the black hole space and time are exchanged, so the time evolution is none any longer in the inside. That however is actually not really clear as long as we don't know the causal structure it takes to remove the singularity.

Anyway, I am also a pizza-base avoider. It's easier the more cheese there is on the pizza.

Best,

B.

Bee said...

Dear Quasar,

Thanks also for the links! I remember when I first read the story about the frog some years ago, I felt really sorry for the frog. It must have been very confusing for the poor animal!

Regarding alleged levitation theories, search for the Maharishi effect. That's some awfully widely distributed nonsense about Yogic Flying.

I don't doubt though that world peace improves when we all sit around and meditate instead of blowing ourselfes up.

However, e.g. read that abstract, read it TO THE END:

We explore phenomenological aspects of a recently- proposed Flipped SU(5) x U(1) supersymmetric GUT which incorporates an economical and natural mechanism for splitting Higgs doublets and triplets, [...]We find typical values of M sub{G} [in the range] 10 superscript{15} to 10 superscript{17} GeV, with M sub{SU} somewhat higher and close to the value suggested by string models. We discuss different mechanisms for baryon decay, finding that the dominant one is gauge boson exchange giving rise to p to e sup{+} pi sup{0}, bar nu pi sup{+} and n to e sup{+} pi sup{-}, bar nu pi sup{0} with partial lifetimes ~10 sup{35 ± 2} y. We show that a large GUT symmetry-breaking scale [...] We analyze the low-energy effective theory obtained using the renormalization group equations, [...] Analysis of the dark matter properties of the theory shows that the LSP decays before cosmological nucleosynthesis, [...]

Finally, we show that the definition of the unified field provided by Maharishi's Vedic ScienceSM supports the identification of the unified field with pure consciousness, [...] Source: DAI, 52, no. 06B, (1991): 3119


Scary, eh?

B.

Bee said...

Dear CIP,

About your hypothesized BH production rate in the LHC. Am I right that this is based on the assumption that extra dimensions are as large as they could possibly be given current experimental constraints?

No.

The production rate is based on the assumption that the new fundamental scale is somewhere around a TeV. The radius of the extra dimension is related to the fundamental scale and the 'usual' Planck scale M_pl through the number of extra dimensions via

M_pl^2 = R^d M_f^{d+2}

Thus, if you set M_f to ~ 1 TeV, the radius of the extra dimensions gets smaller the larger d is. For d>2 the radius is far below the experimental constraints from sub mm measurements. This is possible because the production cross-section is almost independent on d, see e.g. this talk, the slide titled 'Production of black holes'.

The left figure shows the differential cross-section for d=2 and d=6, d between 2 and 6 would result in curves that fall between the shown ones. The right figure shows the integrated total cross-section, you wouldn't see a difference for different d's, that's why its not shown in the plot.

Best,

B.

Uncle Al said...

About those naked singularity black hole remnants... The Outer Limits: "It Crawled Out of the Woodwork," 1963.

Will there now be two sets of mobs being coy for the Media, one decrying the end of the word and the other demanding it?

Bee said...

Hi Uncle,

With remnant I didn't mean a naked singularity. I meant a thermodynamically stable black hole with finite horizon radius.

I am looking forward to the end of the world. Something went wrong, we should start over. How about we make a black hole bomb, have the world cleanly eaten up by it, and create a new and innocent baby universe.

Best,

B.

QUASAR9 said...

as always you are providing me with a surprising and new perspective :-) It's interesting to think about Smolin's baby universes when you allow allegedly intelligent lifeforms to produce black holes. Does that mean that the existence of intelligent life itself can improve the 'fitness' of its own universe?

Bee, NO ONE is producing a Black Hole. A microstate bk supposing one appears, does not even compare to Nagasaki or Hiroshima, and they are both still there 60 years on.

Anyhow, as far as I know Lee doesn't have any extra dimensions in his scenario. Also - and I actually think this is a major shortcoming of CNS - the black holes don't evaporate, nor do they have other time-evolution like accretion or the like. How would that look from the inside, alias the new universe?

Bee, a microstate bk which may or may not disappear into another dimension(?) is not a Black Hole with a singularity which exists in our four dimensional Space 3D+T

If you do believe in CNS and that every black hole is door to a new universe, then also the micro black holes would be such.

I DO NOT BELIEVE IT IT SO. But I do not exlude the possibility that some (more than one) may be wormholes, tunnels to other distant parts of the same SPACE.

I don't quite understand your comment with the singularities. The point is that Lee has removed the singularities inside the black hole, this is one of the central assumptions (besides the almost-continuous and non-random choice of parameters from one generation to the next).

Lee can remove what he likes, that does not make singularities in Black Holes in Space go away

You see, what puzzles me is when our universe came into life through a black hole formed in another universe, then what happens if a stupid observer falls into the black hole? I think, I actually asked Lee about that at some point, he correctly said that inside the black hole space and time are exchanged, so the time evolution is none any longer in the inside. That however is actually not really clear as long as we don't know the causal structure it takes to remove the singularity

I do not believe this universe came into existence thru its own rear-end. This Universe came into existence ex-nihilo.
What a micro-state bk may help to show is that there is another flux like dimension where massless particles do interact with our four dimensions. Is that not what you and JoAnne are looking for, massless (matterless) particles???

You cannot remove the massively (small) dense singularity in a Black Hole. It acretes matter becomes voluminous and expands again. The Black Holes in Space are a posteriori the Origen.

The microstate bk if it appears in the collider will be a posteriori the collision or big bang 'simulation' - not the cause of it.

What does a microstate bk prove or signify to you Bee?
what are its impact relevance or effect on our four dimensions 3D+T?

CapitalistImperialistPig said...

Perhaps I misunderstand, but I thought the energy scale was implied by the radius of the compactified dimensions. If so, wouldn't the the fact that Fermilab hasn't seen black holes constrain any new energy scale to be several hundred GeV+ ? Or is there some other circumstance I'm neglecting?

Bee said...

Dear CIP,

I am not completely sure I understand your confusion, but could it be you are mixing up universal extra dimensions with the here discussed large extra dimension? The radius of the large extra dimensions is much larger than the inverse of the fundamental scale, whereas in universal extra dimensions the radius is typically the inverse of the fundamental scale. (For explanation of both scenarios, see my earlier post about extra dimensions.)

You are completely right that Tevatron data constrains any new energy scale to be above several hundred GeV. For the case of large extra dimensions, the constraint is something like the new fundamental scale has to be > 1.4 TeV or so (for details, see particle data booklet). If you insert this value into the equation above, which connects the new with the usual Planck scale via the volume (~ R^d) of the extra dimensions, you find a resulting value for the radius. It's only for d=1 or 2 that this radius would be directly measurable through sub mm modifications of Newtons law.

Best regards,

Sabine

Bee said...

Dear Quasar,

Bee, a microstate bk which may or may not disappear into another dimension(?) is not a Black Hole with a singularity which exists in our four dimensional Space 3D+T

I really don't know what you are talking about. As far as I am concerned, I hope I made it clear in my post above in which way I refer to micro black holes. Once formed, the micro black holes are in every regard as usual black holes, except that their mass is considerably smaller, and therefore they evaporate very fast.

What defines a black hole is the presence of a horizon. In General Relativity this necessarily implies the formation of a singularity in the inside. However, it is generally believed that this singularity is unphysical and should be removed by an appropriate theory of quantum gravity. Thats at least what I think is the case.

I don't know what JoAnne is looking for, but I'd be happy to find a black hole, which luckily should leave a very clear signature (see above). As long as the black hole carries any gauge charges it can't leave into the extra dimensions. Also, since its formed out of particles in the brane, its initial momentum transverse to the brane is zero.

Best,

B

PS: Regarding highlighing science, have a look at the glooming mice, see also Growth Factors Confer Immortality to Sperm-generating Stem Cells

QUASAR9 said...

Evolution of Galaxies

QUASAR9 said...

Well Bee, I guess if my reply can be retrieved, it means it has not been lost irretriavably, if not it means it has been lost thru some wantum microstate black hole,...

rillian said...

Bee said,

It's interesting to think about Smolin's baby universes when you allow allegedly intelligent lifeforms to produce black holes. Does that mean that the existence of intelligent life itself can improve the 'fitness' of its own universe?

And if so, by implication, this would have already happened. Ken MacLeod wrote a novel around this premise. What constraints does the anthropic principle place on technological societies under such a hypothesis?

Re the Maharishi effect, now that you're in Canada you should ask someone about the Natural Law Party (now sadly offline). They used to take out full page newspaper ads about how, if elected, they would send yogic fliers to patrol the arctic for ICBMs.

Bee said...

Hi Rillian,

Thats interesting. In Germany there was also a natural law party (Naturgesetz Partei). Wikipedia says the party was cancelled worldwide April 30st 2004? For an English version see United States Natural Law Party.

Quasar, did you loose a comment? I am afraid there is currently something wrong with the blogger network or such, I receive several copies of the comments with hours of delay. Best,

B.

Anonymous said...

nice post. one question is what if black holes don't and instead some of the
proposed alternatives to classical
BH's are correct (See gr-qc/0310107)
for one example. How would this change
the scenarios you discussed?

QUASAR9 said...

Hi Bee, blogger does some peculiar things sometimes, when it is busy.
Some people will republish, hence double copies when they go thru, and some will just not republish and comment gets lost.

But yes, I think you've asked this before yourself - where do lost comments (which leave no trace) go.
Do they evaporate into thin air, or just cease to be (never existed)

QUASAR9 said...

PPARC ac uk
It is not important what we call it, as long as we understand what we mean by the term microstate black hole.

Bee you say it has the qualities that define it as a black hole, an event horizon (but no singularity).
An ink drop has an event horizon.
What I want to know, is what a microstate blackhole represents, and what it proves, and its relevance in our four dimensional space
Why do Physicists want to study Particles

QUASAR9 said...

Bee, we (you + I) are moving on two different levels here, looking at two different planes or even dimensions.

a) A collider is not replicating a bigbang producing stars which turn to blackholes
b) Accelerated and collided particles may or may not produce a microstate blackhole

From Ludos: information loss
1) Information is lost
2) Information is retained in a remnant (singularity)
3) information is not lost because of evaporation.
Then the information is preserved as radiation or thermal.

Now we only need to look at cosmological images to know that:
3) Three occurs, we can SEE it
2) Possibly occurs, though we cannot possibly get close enough to see it
1) Would prove there is a transfer between dimensions(?)

Neither 1or3 nor 1&3 exclude 2
And 2 does not claim to exclude 1 and/or 3
---

Bee said...

Dear Quasar,


It is not important what we call it, as long as we understand what we mean by the term microstate black hole.


Yes. So, what do YOU understand under microstate black hole? I think I made clear what I understand under the micro black holes I wrote about, but it seems you have a different understanding.

Bee you say it has the qualities that define it as a black hole, an event horizon (but no singularity).

I didn't say it has no singularity, I said the singularity is not the defining property. Nobody knows whether it would or wouldn't have a singularity, but I personally don't think it would.

An ink drop has an event horizon.

An ink drop definitely has no event horizon. You can perfectly well probe its inside and obtain information about it e.g. by making Rutherford-like experiments or the like.

What I want to know, is what a microstate blackhole represents, and what it proves, and its relevance in our four dimensional space

The micro black holes that I described above represent objects that are subject to quantum gravity. Their observation at the LHC would prove that the 'true' Planck scale is not at 10^16 TeV, but significantly lower. Since the only known way to do this are large extra dimensions, this would be strong indication for these. The relevance of experimental verification for the existence Hawking radiation would confirm decades of theoretical work.

From Ludos: [...]
2) Information is retained in a remnant (singularity)


Yeah, I vaguely recall his strange idea of a remnant. Well, if he defines it this way, then at least I know what he's talking about. But as I wrote earlier, with remnant I do not mean a singularity, but a thermodynamically stable black hole. Though I wouldn't exclude that for some choices of parameters the singularity (if present) could be naked, it would in general have a horizon.

Best,

B.

PS: Indeed I have philosophized where lost comments go to. Though this submitted information might be lost for all practical purposes -- and particularly annoying: lost for the sender -- it is probably technically seen bounced back to somewhere. Just that it doesn't reappear in the form. Somewhere, someone probably has a record of the dead comment. Believe me, if the CIA was interested in it, it would be possible to retrieve it.

QUASAR9 said...

Bee said: "An ink drop definitely has no event horizon."

Bee, the event horizon of an inkblot is its periphery regardless of the fact you can perfectly well probe its inside and obtain information about it e.g. by making Rutherford-like experiments or the like.

The event horizon of a teardrop is its surface, (regardless of the fact that you can perfectly probe its inside and obtain information) - until it splatters on the blotting paper, then the 'new' event horizon may rapidly evaporate

But more seriously there are significant differences to what we are talking about:
a microstate blackhole has gravity?

As for philosophising on information loss, do you think we can recreate yesterday if the information is still there, or is some information irretriabably lost. And another thing can you yesterday be recreated if one were not in it, or is the best we can do like a period film, pretend to recreate (an imperfect copy) of yesterday, full of errors, either glamourized or glossed over, and inevitably influenced by observers. After all every nation painted history to flatter itself.

paul valletta said...

With respect to: An ink drop has an event horizon.

I believe that there could be an analogy to Q9 thinking this?

There is no EVENT horizon of an ink_drop, but what can be a very similar occurrence is it, (inkdrop) has a SURFACE_TENSION.

Now the properties of surface tension are specific to the inkdrops boundary, it surface.

For Blackholes, I believe there was a paper I read that dipicted a certain SURFACE_GRAVITY, relative to the first law of thermodynamics?..I believe it was called "factor of proportionality"?

Just as temperature is is constant for a body in thermal equilibrium, SURFACE_GRAVITY is the same at all locations on the event horizon?

One can imagine that a Liquid's surface_tension, is similar?

QUASAR9 said...

Hi Paul, thanks for that.
You caught my drift.

Further thoughts Bee,
in the macroscale a Star explodes, and 'almost' evaporates, all we have left is hot gas and radiation ... and no massive singularity, no periphery, and hence no Black Hole. The cloud of gas just drifts thru Space like a cloud (nebula)

and in some other cases
the Star implodes we have a massive singularity and I call the space around it a Black Hole with a periphery, gravitational pull (forces), and/or magnetic fields that can attract matter.

Now, I could be wrong, but these appear to be the scenarios astronomical data & images present to us

Plato said...

I can't believe I had missed this whole post and comment section, only to find it here today.

Microstate blackholes have been occupying my mind for some time now.

See:

Star-lite Public Research

What is Natural?

Good post, and very informative by the way. Thanks

Bee said...

Hi Plato,

Thanks! I have added a link to your piece. Best,

B.

rafa said...

Very interesting post. Thanks.

Anonymous said...

Has there been any discussion of the quantum micro black holes that theoretically formed the shape of the universe by growing into filament structure from the time they came into existence after the big bang. Is it truely safe to create a micro black hole given there is no room in quantum for it to radiate back out. Could it form a new galaxy out of the swallowed remnants of our current galaxy. Cheers

fleeting_glimpses said...

why do the fundamental particles themselves not behave as black holes???
i mean matter cant get denser than the most fundamental comprising units, the fundamental particles such as the proton etc.
if black holes were to be denser(i dont know if they are)than the fundamentalparticles...then particles wud hav to overlap....is that possible?

Anonymous said...

The Large Hadron Collider [LHC]at CERN might create numerous different particles that heretofore have only been theorized. Numerous peer-reviewed science articles have been published on each of these, and if you google on the term "LHC" and then the particular particle, you will find hundreds of such articles, including:

1) Higgs boson

2) Magnetic Monopole

3) Strangelet

4) Miniature Black Hole [aka nano black hole]

In 1987 I first theorized that colliders might create miniature black holes, and expressed those concerns to a few individuals. However, Hawking's formula showed that such a miniature black hole, with a mass of under 10,000,000 a.m.u., would "evaporate" in about 1 E-23 seconds, and thus would not move from its point of creation to the walls of the vacuum chamber [taking about 1 E-11 seconds travelling at 0.9999c] in time to cannibalize matter and grow larger.

In 1999, I was uncertain whether Hawking radiation would work as he proposed. If not, and if a mini black hole were created, it could potentially be disastrous. I wrote a Letter to the Editor to Scientific American [July, 1999] about that issue, and they had Frank Wilczek, who later received a Nobel Prize for his work on quarks, write a response. In the response, Frank wrote that it was not a credible scenario to believe that minature black holes could be created.

Well, since then, numerous theorists have asserted to the contrary. Google on "LHC Black Hole" for a plethora of articles on how the LHC might create miniature black holes, which those theorists believe will be harmless because of their faith in Hawking's theory of evaporation via quantum tunneling.

The idea that rare ultra-high-energy cosmic rays striking the moon [or other astronomical body] create natural miniature black holes -- and therefore it is safe to do so in the laboratory -- ignores one very fundamental difference.

In nature, if they are created, they are travelling at about 0.9999c relative to the planet that was struck, and would for example zip through the moon in about 0.1 seconds, very neutrino-like because of their ultra-tiny Schwartzschild radius, and high speed. They would likely not interact at all, or if they did, glom on to perhaps a quark or two, barely decreasing their transit momentum.

At the LHC, however, any such novel particle created would be relatively 'at rest', and be captured by Earth's gravitational field, and would repeatedly orbit through Earth, if stable and not prone to decay. If such miniature black holes don't rapidly evaporate and are produced in copious abundance [1/second by some theories], there is a much greater probability that they will interact and grow larger, compared to what occurs in nature.

There are a host of other problems with the "cosmic ray argument" posited by those who believe it is safe to create miniature black holes. This continuous oversight of obvious flaws in reasoning certaily should give one pause to consider what other oversights might be present in the theories they seek to test.

I am not without some experience in science.

In 1975 I discovered the tracks of a novel particle on a balloon-borne cosmic ray detector. "Evidence for Detection of a Moving Magnetic Monopole", Price et al., Physical Review Letters, August 25, 1975, Volume 35, Number 8. A magnetic monopole was first theorized in 1931 by Paul A.M. Dirac, Proceedings of the Royal Society (London), Series A 133, 60 (1931), and again in Physics Review 74, 817 (1948). While some pundits claimed that the tracks represented a doubly-fragmenting normal nucleus, the data was so far removed from that possibility that it would have been only a one-in-one-billion chance, compared to a novel particle of unknown type. The data fit perfectly with a Dirac monopole.

While I would very much love to see whether we can create a magnetic monopole in a collider, ethically I cannot support such because of the risks involved.

For more information, go to: www.LHCdefense.org

Regards,

Walter L. Wagner (Dr.)

Groan said...

Wagner is suing LHC.

http://cosmiclog.msnbc.msn.com/archive/2008/03/27/823924.aspx

http://cosmiclog.msnbc.msn.com/
archive/2008/03/27/823924.aspx

Anonymous said...

Micro black hole as energy source?

If a Planck-sized remnant remains after the mbh spins down, then this question arises: what happens when the mbh next encounters a particle? Presumably, it immediately emits the particle as Hawking Radiation and reverts to its stable remnant state.

Might this make the MBH a perfect mass-to-energy converter and hence an ideal energy source, converting mass entirely into energy?

Bob - SoftwareEngineer/EE

Bee said...

Hi Bob,

Please read this. Best,

B.