Hawking Versus Unruh Temperature as a Measure of the Health of the Equivalence Principle by Douglas Alexander Singleton

Dear Douglas,

Although the technicalities of comparing Hawking and Unruh's results are beyond me, I would like to comment on two things in your interesting essay: If one sets aside Einstein's rather arbitrary decision in SR to have c constant and the resulting spacetime concept, the Equivelance Principle in GR reduces to the curvature of the energy streamlines (or of the equipotential surfaces). This reduces it to simple refraction with variable speed of light in a region of gradient index of refraction (Eddington 1920). In other words the mechanics of classical deceleration resulting in curvature!

My other point is that in my theory the Holographic Principle can be explained as the resultant of physical node-node inductive forces within the ordered ether lattice of space, including a black hole. See attached Fig. 27 of the following paper to illustrate GR as refraction, and Fig. 11 to show the mechanism by which the Holographic Principle can be understood. Beautiful Universe Theory I hope these two concepts will somehow one day mesh in with your interesting research. If you have time I hope you will also have a look at my fqxi essay Fix Physics!

With best wishes,

VladimirAttachment #1: 1_BUFIG11.jpgAttachment #2: BUFIG27.jpg

Dear D. Singleton,

I forgot that this system does not like backwards facing carrot symbols, and it cuts things off. So I repost this with I hope things fixed.

I think there might be some problems with this. The substitution of the gravitational acceleration g = (1 - 2m/r)(m/r^2) into the Unruh temperature equation may only apply in the near horizon condition where r = 2m d, 2m >> d. The question is whether this is really a violation of the equivalence principle or a breakdown in the appropriate approximation for this substitution.

It is further difficult to know what is meant by Unruh effects in the region 2m > r. There is no comparable physics for the Unruh effect at a distance d = c^2/g, for d outside the Rinder wedge, or 0 > d.

I will try to give this some thought, but I think there is a question of whether this represents a real departure from the equivalence principle or whether this reflects T_H =~ T_U is correct only with the near horizon approximation.

Cheers LC

Dear LC,

Thanks for reading my essay and your questions. You are correct that inside the horizon there are difficulties. However I do note this by saying that on crossing the horizon the analysis will proceed by heuristic arguments and conjecture. One point is that at and inside the horizon one can not "stand still". This is already indicated by the fact that the local acceleration for an observer who is at rest near the horizon approaches \infty as one goes to the horizon.

But outside the horizon one is in a regime where one can trust the calculation of the local acceleration. For an observer at a fixed distance from a gravitating object one can straightforwardly calculate the local acceleration. Then taking this finite acceleration one can think of a Rindler observer with this acceleration. In turn this Rindler observer will detect an Unruh temperature proportional to a=(GM)/R^2. This temperature will be lower than the Hawking temperature of an observer in the field of a gravitating body. Thus the tow observer will measure the same local acceleration but will measure different temperatures.

Best,

Doug

Dear Azzam,

Thanks for reading my essay and for your comments. I will try to fully read you essay and send comments.

Best,

Doug

Dear Jayakar,

Yes string theory may have something interesting to say about the EP. Thanks for your post and for reading my essay.

Best,

Doug

Dear Vladimir,

Thanks for reading my essay and your comments. I will try to read your essay and send comments as well. The illustrations look very nice.

Best,

Doug

I am thinking of bending some metal on this. I would feel better if my concern over whether this reflects a breakdown in an approximation is answered.

The accelerated frame near the event horizon observes the outside world "speed up," for units of proper time on this frame correspond to very large units of time is asymptopia. As the accelerated frame approaches the horizon, which requires a larger acceleration, we may think of adiabically moving this situation to the stretched horizon. The distinction between this frame and the frozen appearance of a freely falling frame on the stretched horizon as observed from the outside are indistinguishable. This flies in the face of some standard physics, where physics is written according to inertial frames. There is an asymmetry between inertial and accelerated frames, which I think is in greater generality removed. I reiterate what I wrote the other day on the accelerated frame below.

For the accelerated observer the life time of the exterior world races by in a flash. For a stellar mass black hole it requires billions of g-forces to remain a few meters from the horizon, and to get within centimeters requires about a billion billion g's of acceleration. If by some means an observer could do this the outside world would be racing by, say for a small proper time with t = g^{-1} cosh(gs). So the proper time element is s ~ g^{-1}ln(gt) for a time unit t outside. As a result for t the lifetime of the black hole ~ 10^{67}year, g in units of distance ~ 1cm ~ 10^{-10} sec ~ 10^{-17}year the proper time the observer on the accelerated frame observes the BH to evaporate is

s ~ 5x10^{18} years.

This is much shorter than the BH life time measured by the exterior world. Assume you get that acceleration up to 10^{33}cm^{-1} or 10^{43}sec^{-1} or 10^{50}year^{-1}, then you are hovering practically on the stretched horizon. The BH evaporates in about 10^{-42} seconds, or close to the Planck unit of time! Bang!; which means all that ingoing and outgoing radiation which interacts with the black hole hits you at once is a colossal thunderclap. The event horizon appears for larger g close in to be more of a singularity, or a surface region of huge energy density that is radiating and absorbing energy at a ferocious rate.

Cheers LC

Hello Mr Singleton,

And if we arrive to put a light near this BH and if we superimpose the holographic concept ? we could see it :)

You know I beleive strongly in the equivalence principle. It is an important parameter at all scales you know.

The works of hawking are indeed relevant about the hawking radiations correlated with heat and temperature.If I could, I will say him(Mr Hawking) that it is possible to see what is really our BH. first , what is really our central BH of our galaxy. we cannot really see what are their productions. I beleive that they are productors also of complementary matters.But we cannot see them just due to their mass. My equations are relevant. I ask me how we can see it really. I think that we can lighting up it. Of course it is not really easy.But it is possible.

The violations of the equivalence principle are not really rational you know.

That said, I liked to read your essay.

Regards

Douglas,

The equivalence principle is quite useful in that it converts the gravitational redshift into Doppler shift and vice versa, as shown in this quotation:

http://galileo.phys.virginia.edu/classes/252/general_relativity.html

Michael Fowler, University of Virginia: "What happens if we shine the pulse of light vertically down inside a freely falling elevator, from a laser in the center of the ceiling to a point in the center of the floor? Let us suppose the flash of light leaves the ceiling at the instant the elevator is released into free fall. If the elevator has height h, it takes time h/c to reach the floor. This means the floor is moving downwards at speed gh/c when the light hits. Question: Will an observer on the floor of the elevator see the light as Doppler shifted? The answer has to be no, because inside the elevator, by the Equivalence Principle, conditions are identical to those in an inertial frame with no fields present. There is nothing to change the frequency of the light. This implies, however, that to an outside observer, stationary in the earth's gravitational field, the frequency of the light will change. This is because he will agree with the elevator observer on what was the initial frequency f of the light as it left the laser in the ceiling (the elevator was at rest relative to the earth at that moment) so if the elevator operator maintains the light had the same frequency f as it hit the elevator floor, which is moving at gh/c relative to the earth at that instant, the earth observer will say the light has frequency f(1 + v/c) = f(1+gh/c^2), using the Doppler formula for very low speeds."

You don't think this analysis based on the equivalence principle should be abandoned do you?

Pentcho Valev pvalev@yahoo.com

Dear Mr. Dufourny,

Many thanks for your comments. You are correct that from the thought experimetn I present in my essay one could as well take the stand that the EP is correct and then the implication would be that there is something "wrong" with Hawking/Unruh radiation (e.g. Hawking radiation does not exist, or does not have the form given by Hawking). In fact there are researchers who questin the existence of Hawking radiation. For exmaple

"Do black holes radiate?"

by Adam D. Helfer Rept.Prog.Phys. 66 (2003) 943-1008

e-Print: gr-qc/0304042 [gr-qc]

also there are researchers who question the existence of the Unruh effect

"An Example of a uniformly accelerated particle detector with nonUnruh response",

by A.M. Fedotov, N.B. Narozhny, V.D. Mur, V.A. Belinski

Phys.Lett. A305 (2002) 211-217

e-Print: hep-th/0208061 [hep-th]

Thus if one wanted to take the EP as exact under all conditions then my thought experiment would be an argument (along the lines above) of the non-existence of Hawking/Unruh radiation.

However, my choice was to assume the EP was violated and look at the consequences.

Best regards,

Doug

Hi Douglas. Quantum gravity (and the union of gravity and electromagnetism as well) definitely require observer and observed, instantaneity, and a fundamental balancing and equivalency of inertia and gravity. Balance and completeness and the combining, balancing, and inclusion of opposites is essential.

Ultimately, in a truly unified and FUNDAMENTAL understanding of physics, space must be shown as invisible, not visible, and visible in a balanced fashion in keeping with the above paragraph. Temperature is basically averaged [FUNDAMENTALLY] given such a unification.

What are your thoughts on this please? Thanks.

Dear Douglas Alexander Singleton,

I hope to discuss with my idea which is related to my MSRT http://fqxi.org/community/forum/topic/1272 and is related to your paper.

According to my theory, since time dilation and Lorentz factor is depending on the difference of the vacuum energy. Thus I found, in the case of the train moving with constant speed v, then for the stationary earth observer the vacuum energy of this train must be higher than the vacuum energy of the earth surface. Thus the temperature inside the boundaries of the moving train will be increased. And if the velocity increased also, the temperature will increase also. This increase in the temperature is because of the increase of the vacuum energy which is related to the velocity of the train. But according to my MSRT, there is no Unruh radiation, where I proof that. What is your opinion for my idea? I hope to hear from you.

Azzam

Hello ,

Is it necessary to invest in already knwown results ? the monney is a tool and it must be utilized witht he biggest wisdom.

The violations are not really foundamental you know.

The Bh radiates probably but their motions are above the fermions at my humble opinion.In fact the real interest is to fid the fractal above the weak and the strong int. more the electromagnetism. I beleive that the volumes of spheres are the secret......see the stabilities of informations.

In fact the aim is to class the BH and the volumes of stabilities. I beleive that the works of Hawking are relevant considering a pure thermodynamical correlation. The BH can be classed. The BH have a lot of properties correlated with the rotating spheres. The kinetic energy and the potential energy are always relevant.

In fact, these BH are like the stars, they produce the matter with all its fractalization and its complexity. The quarks, the neutrinos, the gravitons,muons,.... but not bosons at my humble opinion. In fact they are above the SR. It is intringuing considering the sortings and the synchronizations of informations in a pure general point of vue.

I beleive strongly that the volumes of BH increases more we go towards our main central BH of our Universal sphere. It is relevant considering the other productions of matters from these central spheres. The steps appear when the volumes and the rotations are inserted. The pure heat and thermodynamics can showing the road towards these central spheres. The system is a finite serie.

Regards

Hi Frank,

Thanks for your comments on my essay. I'm not sure I completely follow the question but let me give it a try. You seem to be saying that spatial dimensions should become "invisible" in a unified theory. Generally in things like string theory the trend goes the other way -- as one probes higher energy scales the extra dimensions which had been hidden, compactified or invisible "open" up and become visible. Thus in theories with extra dimensions like string theory more spatial dimensions open up/become visible as one goes toward the unification scale.

However, there is recent work which postulates that dimensions compactify or curl up at larger energy scales. This idea can be found in

"Detecting Vanishing Dimensions Via Primordial Gravitational Wave Astronomy",

Jonas R. Mureika, Dejan Stojkovic, Phys.Rev.Lett. 106 (2011) 101101

e-Print: arXiv:1102.3434 [gr-qc]

and the references therein. In this scheme (which is based on the causal dynamical triangulations of GR) the spatial dimensions reduce at larger energy scales.

Something along these lines might be what you had in mind?

Best regards,

Doug

Hi Azzam,

In the case you are considering (a train moving with constant velocity) you are correct -- there is not Unruh radiation. To observe Unruh radiation one must go to an accelerated frame. Also although there is no definite, undisputed evidence for the Hawking or Unruh radiation there have been recent claims that analog Hawking radiation has been detected in a system where ultra short, high intensity lasers pulses are aimed at a certain type of fused silicate glass. This creates *two* optical, analog event horizons from which something like Hawking radiation was detected. The link for this is

http://phys.org/news204866995.html

and the technical paper was published in PRL in 2010. There are also claims that the Unruh effect can be (and in fact has been) detected in through the shifting of expected populations of electrons in storage rings of particle accelerators. This work is

"Electrons As Accelerated Thermometers",

J.S. Bell, J.M. Leinaas (CERN). Nucl.Phys. B212 (1983) 131

CERN-TH-3363

Both of these claimed experimental detections of Hawking radiation and Unruh radiation have some loop holes so that the claims are not completely accepted, but at least there is some work in the direction of experimental verification of these effects.

Now your second point seems to revolve around the behavior of temperature under Lorentz transformations. This is an open and still debated subject. A relatively recent paper on this subject is

"Inverse Temperature 4-vector in Special Relativity", Zhong Chao Wu

Europhys.Lett.88:20005 (2009) ; arXiv:0804.3827v4 [gr-qc]

I'm not sure I agree with the conclusions of this paper but it does list all three possible transformations of temperature namely:

T=T_0 *gamma

T=T_0 /gamma

T=T_0

(where gamma is the usual SR gamma-factor and these possible transformations and the references where they were proposed are given in eqns. (1)(2) (3) at the beginning of the paper. Thus your proposal above -- that the temperature increases with relative velocity -- seems to be in line with the suggestion T=T_0*gamma.

There is also the suggestion (which can be found in the beautiful but nonstandard physics "textbook" http://www.motionmountain.net/) that it only makes sense to define a temperature in the frame of reference where the center of mass of the object whose temperature is to be measured is at rest.

I'll try to read your essay more closely to see if I have additional comments.

Best regards,

Doug

Dear Douglas Alexander Singleton

Thank you very much for your previous comment.

In my theory (the equivalence principle) difference temperature is one term that affected on the difference of the vacuum energy, and thus affecting on the Lorentz factor. The other terms are the effective density and pressure. Most of the quantum tunneling experiments and entanglement are performed in a very low temperature. That means according to my theory, in the very low temperature, events and the motion of clocks will be moved on in a faster rate than at higher temperature. For example, in the case of tube of length L in the lab. and the temperature of the tube is very low compared to the temperature of the lab. Thus according to my theory the motion of the clock inside the tube will be faster than the motion of the clock of the lab. That is because according to my equivalence principle, the observer of the lab is equivalent to move with speed v relative to the frame of the low temperature of the tube. Thus from the difference of the temperature of the tube and the lab we can determine the difference of the vacuum energy and thus determining the Lorentz factor, and then determining how the clock inside the tube moving faster. This case is same as when the rider of the moving train with constant v determined by his clock the time t', and when he stopped his train he will find the clock of the earth surface computed more time t where t=gama*t' where gama is the Lorentz factor. Thus if I'm right in my theory and equivalence principle, that led me to ask myself, if the increasing of the temperature of the medium led to the vacuum energy to increase, and thus led to the Lorentz factor to increase, thus for the moving train with constant velocity v, relative a stationary earth observer must observe there is an equivalent temperature increase inside the medium of the moving train, where this increase in temperature can be determined from the Lorentz factor. Thus we can develop this idea in the case of gravity, and thus we can illustrate the Hawking radiation is right. Where from this principle, for any mass, from the Schwarzschild geometry we can determine the Lorentz factor which is depending on the distance from the center of mass. Thus from this Lorentz factor we can determine the equivalent temperature at any distance r from the center of mass. Relative to Hawking radiation, since the Lorentz factor is very high near the event horizon, there must exist a high temperature, and each time we approach from the event horizon the Lorentz factor will increase, thus the temperature will increase also.

Sincerely,

Azzam

Dr. Singleton,

I noticed your statement in the abstract :"To date there has been no definitive, experimental evidence for a problem with general relativity as the proper theory of gravity."

Although the following is not definitive, what is your opinion of the following statement?

"An alternative explanation of the accelerating expansion of the Universe is that general relativity or the standard cosmological model is incorrect. We are driven to consider this prospect by potentially deep problems with the other options." REPORT OF THE

DARK ENERGY TASK FORCE

Regards,

Jeff Baugher

Dear Mr. Baugher,

I agree with this statement. As I read the statement it says that we need to consider that GR and/or the standard cosmological model may be wrong. The current cosmological picture is that GR and the current cosmological picture are correct and that one only needs to add some field/fluid/stuff, which is generically called dark energy, to account for accelerated expansion rate of the Universe. But as well it could be possible that the accelerated expansion is due to some modification of GR. In some sense my essay leans in this direction although I focus on modification at short distances rather than cosmological distances.

And even if there is no *definitive* experimental evidence, currently, that GR is wrong there are plenty of hints that GR needs to be modified: (i) the inability to quantize gravity; (ii) dark matter (this might be due to some modification of GR at galactic distance a la modified Newtonian dynamics); (iii) dark energy (again this might be evidence for modifcation of GR rather than the existence of some substance with the odd properties of dark energy); (iv) the singularities at the center of a BH. Thus there is strong circumstantial evidence the GR will need to be modified at short and/or long distance scale.

Best,

Doug

Doug,

The fact that Hawking radiation and Unruh radiation are different does not show any failure of the equivalence principle (EP). The EP is local, while Hawking radiation is generated in an extended region. If you are in a small elevator, and see radiation coming at you, you have no way of knowing whether it is Hawking radiation or radiation due to some other source. The EP only applies to what goes on within the elevator (local), not to what external boundary conditions the elevator is likely to have.

It is no different from the standard example of an observer standing on a planet (near 0 Kelvin). This observer observes no Unruh or Hawking radiation, but he feels a force on his feet.

Regards,

Jack