Strom in Waterloo, Ontario

I took this photo tonight from my balcony at Waterloo, where I was spectator of a rain storm. after many attempts I finally succeeded to take this shot from a lightning.

Irrelevant news from nature to loop quantum gravity

Today I read this article from BBC that LHC results put supersymmetry theory in trouble.

The results do not rigorously demonstrate anything because Strings can exist without low-energy supersymmetry of Loops with supersymmetry. I do not understand why the community of loop quantum gravitists are this much happy about it?! Its certainly bad news for preliminary string theory, but how about loop quantum gravity? Loop Quantum Gravity does not rely on superstring theory but it can certainly handle that. Loop quantum gravity certainly is an alternating theory, but there are many other candidates to seek for using the foundations of quantum mechanics.

But certainly this result is without doubt so important to be argued for a long time between experts.

The paper of Kondo noise ...

I and Frank worked on it, was accepted for publication in Physical Review B in the third week after submitted. This is a new score in short-time reviewing process perhaps because we paid it off from working on it for almost a year!

If you are working on the critical current noise in superconducting materials or in general you deal with superconducting qubits or SQUIDS, reading this paper is highly recommended.

You will find in it a good analytical approach to understand the complicated physics of a magnetic impurity inside a Josephson junction. With the consistency it provides with the Wilson type renormalization group method so far was used in the Kondo community, it equips us to study the critical current noise in a tunnel junction in the presence of a few free Oxygen molecules inside the tunnel junction oxide layer.

Theory Canada 6 in the city of Corner Brook in Newfoundland, Canada was exciting and interesting. The nature of the city is unique and the core idea of the conference was intriguing: some of the Canadian theorists who due to the wide geography of this country cannot meet each other in a regular base gather in one place a few days before CAP conference and collaborate on exchanging ideas and thoughts.

Mohammad H. Ansari

Noise and microresonance of critical current in Josephson junction

Along with Frank Wilhelm I enjoyed working on the noise study of a Josephson junction. The results appeared today at

arxiv.org/abs/1106.4794

We analyze the impact of trap states in the oxide layer of a superconducting tunnel junctions, on the fluctuation of the Josephson critical current, thus on coherence in superconducting qubits.

Two mechanisms are usually considered: the current blockage due to repulsion at the occupied trap states, and the noise from electrons hopping across a trap. We extend previous studies of noninteracting traps to the case where the traps have on-site electron repulsion inside one ballistic channel.

The repulsion not only allows the appropriate temperature dependence of 1/f noise, but also is a control to the coupling between the computational qubit and the spurious two-level systems inside the oxide dielectric.

We use second order perturbation theory which allows to obtain analytical formulae for the interacting bound states and spectral weights, limited to small and intermediate repulsions.

Remarkably, it still reproduces the main features of the model as identified from the Numerical Renormalization Group.

We present analytical formulations for the subgap bound state energies, the singlet-doublet phase boundary, and the spectral weights.

We show that interactions can reverse the supercurrent across the trap.

We finally work out the spectrum of junction resonators for qubits in the presence of on-site repulsive electrons and analyze its dependence on microscopic parameters that may be controlled by fabrication.

Meet other creatures

Meet them in these scales of a meter:

• 10^-35:  Quantum gravity domain. Planck's length.
• 10^-30:
• 10^-28:
• 10^-24: Neutrino
• 10^-21:  Perons, the ingredients of quarks.
• 10^-18: Quarks. Electron cores.
• 10^-15: Protons.
• 10^-14: size of light nuclei.
• 10^-12: Gamma ray wavelength. 
• 2*10^-12: electron Compton wavelength.
• 5*10^-12: X-ray wavelength.
• 2.5*10^-11: distance between two Hydrogen atom nuclei.
• 3.1*10^-11: distance between two Helium atom nuclei. 
• 7.0*10^-11: distance between two Carbon atoms nuclei.  
• 10^-10: distance between two Sulfure atom nuclei.
• 5*10^-10: width of Protein alpha Helix.
• 10^-9 (1 nano meter): Carbon nanotube.
• 2*10^-9: the smallest transistor gate of microprocessor.
• 3*10^-9: thickness of DNA.
• 10*10^-9: the width of cell membrane.
• 50*10-9: ultraviolate wavelength.
• 90*10^-9: HIV.
• 300*10^-9: Violate wavelength.
• 500*10^-9: largest virus.
• 600*10^-9: red light wavelength.
• 7*10^-6 (7 micrometer): red blood cell.
• 10*10^-6: infrared wavelength. Fog droplet. White blood cell. 
• 50*10^-6: Pullen grain. Silt particle. 
• 10^-4 (a tenth of milimeter): smallest things visible to naked eyes. Width of human hair.
• 2.5*10^-4: human egg. 
• 3*10^-4: computer pixel.
• 5*10^-4: salt crystal grain. Thickness of human skin. Largest bacteria. Pencil lead.
• 7*10^-4: thickness of credit card. 
• 10^-3: Ant. Sesame. etc. 

The Fritz London Prize 2011

is happy to hear the Fritz London Prize - highest award in low temperature physics after the nobel - is awarded to Hans Mooij in recognition for his experimental contributions to the understanding of nonequilibrium superconductivity, Josephson flux qubits, etc; at the same time to Gerd Schön in recognition of his theoretical contributions to the understanding of superconductivity in mesoscopic systems, including charge qubit; as well as to Humphrey Maris in recognition for his original theories and experimental discoveries in liquid helium, concerning phonons, Kapitza resistance, levitation, nucleation, electron bubbles and vortex imaging.

Conference Announcement NCMT 2011

Another major event in the region of South Western Ontario for the community of nanostructure phyicisits:

International Conference on Frontier Topics in Nanostructures and Condensed Matter Theory
March 9-11, 2011at Western

URL: http://ncmt2011.uwo.ca/

The Kondo theory

Additional unwanted qubits in a phase qubit due to the Kondo effect.
Simmonds et.al. Phys. Rev. Lett 2005 

The Kondo effect is one of the interesting features of low temperatur physics where temperature is seen not to play as a smoother, instead it ruines the results taken from perturbation theory.   Last Monday I presented a talk titled "the Kondo effect" in a Colloquium at the Institute for Quantum Computing IQC in Waterloo.  It was a good opportunity to face with some interesting questions and comments...

In this talk I presented two exotic behavior of electron in low temperature, one in a quantum dot, and the second in the Josephson junction between two superconductors.  In a quantum dots I explained the Kondo plateaus predicted in 1988 by Glazman and Raikh in JETP Lett. and they observed by van der Wiel et.al. Science 2000. In the second half, I explained how this effect can causes the presence of additional unwanted qubits interacting with the computational qubit. And finally our recent idea of how to suppress them to prevent errors on computations... 

How much snow

In the last three weeks there was about 2 meters of snow falling over London Ontario that caused the University to be closed for 4 days and the city buses not to operate for almost two days, due to the heavy load of snow on roads.


How much this city became heavier then? 


With the area of almost 400 (km^2), so the volume of snow is 0.8 billion (m^3). The mass density of freshly fallen snow is around 10% of that of water, let let be it 100 (kg/m^3).


So the total mass of the snow is huge: 80 billions (kg). 


This is equal to the mass of a near-Earth asteroid that caused a brief period of concern in December 2004 because initial observations indicated a small probability that it would strike the Earth in the year 2029!


How much power does this mass create?


If we consider the speed of rain droplets is a few meters per second, let us consider the speed of snow is at least 0.1(m/s), which produces the kinetic energy 1/200 (J/kg).  This much snow fell on the city in 4 days therefore the rate of falling was 80 billions kilograms per four days, or 200,000 kg/s. The total power is 1000 Watts.


This snow generated 5% of the solar power radiated by sun over this city.
    

Met him!

I remember last month in June, after staying up all night long at Student Life Center (SLC) of UWaterloo reading a paper on Gamma ray bursts and another one on noise in Josephson junctions, and rederiving all equations in them, I felt have no energy to walk 4km back home at 4AM. For the first time I slept on a sofa, it was not in fact a sofa it was quite I'd call a "recliner". In the middle of night this center is the only place open to students 24/7 for gathering, dancing, eating, drinking, listening, talking, studying, etc.

I woke up around 10 AM with freshly brewed coffee smell in the area. After I washed and had the best coffee with a big muffine, I went out to stretch and walk back home to take a shower. Right in front of my eyes I saw two bodygurads and Barak Obama. He was 2 meters away from me, coming out of a door and about to get into a car and there was nobody around. I was stoned to see this scene and thought I am dreaming. THe car door was open but before he gets into the car, he noticed my astonishment and stepped forward for a meter bending toward me and said hello, I am Barak, who are you? I was confused and totally mixed up. I said my name in the format I wrtite it on scientific papers: I said I am Mohamamd H. Ansari. He laughed and said "nice to meet you Mr. Mohammad H., What is the H. stands for?" and I said "Hossein". He laughed and said: "we have a name in common. Have a nice day"

On the way back home I could not believe what did I see and was reviewing the moment and laughing at how I introduced myself, it was so awkward! :)

Updates, December 2010: Since then I checked the news many times and there is nothing in the univerity news and publicity about the visit of the preseidnet from a random university. I am not surprised to hear today that the chair of our university has been promoted by the Queen Elizabeth to serve as the governor Gerneral of Canada, which is the federal representative of the Canadian/British monarch, i.e. the representatitive of the Queen in my country. Did the visit have anything to do about this news? I never know.

QISS 2010

The wonderful QISS 2010 workshop was definitely a success for the organizer Institute. We saw the most modern form of qubits in semiconductors, superconductors, and the buckyball fullerenes. More information can be found in here, where the talks are supposed to become available online soon.

Quantum Amplification Effect on black holes

Black holes radiate.

But recently it is shown they even more radiate!

In fact when their horizon fluctuates, they radiate on two or three frequencies that are heavily resonated, like a quantum amplifier.

These lines are at the range of frequency sensitivity that INTEGRAL may become able to find them. Perhaps we have observed them and do not recognize them as black hole QAE lines.

These lines could be foud in evenly or unevenly spaced fashion. in fact, Yakov Bekenstein and Viatcheslav Mukhanov predicted these lines (if are more than two) are exactly evenly spaced. With the support of theories that predict the spectrum of area scaling with the square-root of integers, we predicted they must be found in an unevenly-spaced fashion.

Details can be found in my recent Physical Reviews D paper...



This figure illustrates a quantum black hole horizon in the vicinity of a null boundary (the black sphere). In other words, you see a black hole as the interior black sphere underneath a discrete shell (the outer shell) that represents the hole's horizon area fluctuations.

The spectrum of a black hole radiation should be discrete, intense, and narrow line on top of weak the Hawking radiation.

The search for these lines in observational data is continued...

How to work with jpeg2ps software in Windows

How to work with jpeg2ps software in Windows:

1- After installing GSView (read here for instruction), download jpeg2ps from here, (thanks to sourceforge.com!)

2- After downloading is finished, click on the file and install the software. Note at what folder it's going to be installed. Its default location is usually at "C:\Program Files\GnuWin32\"

3- (Copy and) paste a JPEG, which you want to convert it into eps, into "C:\Program Files\GnuWin32\bin".

4- On Windows "Start" click on "Run" and write in its empty box "cmd". A black DOS window will appear inside which a default directory is written, usually it is "C:/Program Files/Username>". Each time you write "cd.." in front of the ">" and enter this folder goes one root backwards, so by repeating this you can go back to "C:>". Write "cd Program Files\GnuWin32\bin" or "cd [The "bin" folder address where you installed jpeg2ps at]. Now you are where the software jpeg2ps is! (If you are DOS expert you know how to write shortcut.)

5- Write "jpeg2ps" and you'll see the option menu. It is time now to actually convert a sample picture. Assume the file "sample.jpeg" (which is located at C:\Program Files\GnuWin32\bin) should be converted to EPS.

6- Write "jpeg2ps sample.jpeg > filename.eps". Doing this will create the file "filename.eps" in the folder C:\Program Files\GnuWin32\bin. This will be your desired eps file. You can change the resolution as well as other options.

Enjoy!


More information:
How to convert quality jpeg images into eps. (Guage Invariance)

Timing backwards

Let's assume we are watching 10 seconds of a basketball game. It is right at the moment when two players are standing near the basket and the ball is passed from one player to the other who reside under the basket. This player after, grabbing the ball, turns about his waist and shoots the ball into the basket such that the ball enters into the net from its below. We no longer see the game.

Now consider time goes backwards. The ball enters the basket from above, one player grabs it and passes it to the farther player. Consider the way how the players act is such that we cannot distinguish the difference between the first scenario and the second one only by watching their action.

It seems in the lack of the rest of the play, we cannot distinguish between these two degenerate scenarios. However, there is a tiny difference between the two that breaks the degeneracy. In fact, by noticing that we can distinguish between the correct and the backward time directions. Guess what is the point?

Mohammad H. Ansari

A new solution to the statistics of hard elongated objects

A new solution to the statistics of hard elongated objects
M.Ansari, [0911.5312] (cond.mat/statistical Mechanics)

On: an analytical solution to the statistics of hard elongated objects (e.g. needles, rectangles, ellipses, etc)

Elasticity theory describes how a system under distortion is mechanically deformed. There are two approaches to quantitatively study this. The traditional approach is
to analyze the dislocation of fluid rigid boundaries. Depending on the properties of fluid (e.g. viscosity, compressibility, etc.) a variety of different cases appears.

The other approach, which is of our interest, replaces fluid with discrete objects and studies the short-range interaction between these objects. If the objects are spherically-symmetric, their alignments lead to translational ordered/disordered phases.

Frenkel et.al. in a series of papers developed a method that enables to analyze the stress and elasticity of hard spherically-symmetric objects.

A natural generalization is to replace the spherically-symmetric objects with elongated objects. These objects carry a coupling between their translational and rotational degrees of freedom and display orientational ordered/disordered phases; similar to liquid crystals.

Recently, in a series of papers a formalism for direct calculation of elastic properties of hard non-spherically symmetric objects was proposed by Murat, Kantor, and Farago. They considered hard stiffness for these objects in order to prevent the influence of orientational degrees of freedom into kinetic energy. Their method was
developed on the basis of different types of central and non-central short-range interactions; central potential depends only on the relative distance between particles, whereas noncentral potential depends on individual object orientations.

This formalism has been so far applied in different problems such as the wrapping of proteins in DNA, the ordering of complex liquids systems and percolation transitions, and the jamming transitions.

However, this formalism is hard to be solved analytically and a Monte-Carlo simulation should been used to extract its physical properties. Kantor and Kardar in
proposed a self-consistency check for this formalism in one dimension, where instead of non-spherically symmetric objects, needles are applied. The center of needles
are on a line and the angle of each needle orientation is randomly chosen. They solved this model by transfer matrix method numerically and reported an agreement
between the numerical and MC results.

The purpose of my recent publication is to reconsider elongated objects in one dimension and propose an analytical solution that, in our opinion, goes a step forward since it allows to obtain analytical formulation for some collective properties obtained so far only numerically.

To this end, we eliminate the dependence of free energy on the absolute value of an angle, thus make the orientation completely isotropic.

Interparticle distance and elasticity coefficients are derived into analytical formulations and verify the exact model results of Kardar and Kantor. We generalize our formalism to cover different types of elongated objects and repeat to derive them and verify recent results. This formalism allows to evaluate other properties of the same class, such as inverse distance between needles.

We verify the inverse distance law of sound pressure in high densities. As expected from a previous study on spherically-symmetric object, in needles model the expectation value of inverse distance below a critical pressure does not scale as the inverse of distance.

Energy released by Volcano and earthquake

The energy released from a Volcano is 10^13 Joules. The chemical bond energy between carbon molecules to form 12 grams of carbon compound is typically 10^5 Joules. With the 10^13 Joules one can vaporize 10^3 Tonnes of Carbon.

In the case of an earthquake of magnitude 6, about 10^15 Joules of energy is released, some of these are released before the main shock. This amount is necessary to vaporize 10^5 Tonnes of carbon. Although most of the energy is released in the thermal form, but anyhow should it be unrealistic that one studies the formation of an earthquake cloud before an earthquake on top of the region gaining this energy.

P.S.> The above picture is taken from here.

Reports on NPB findings from M.H. Ansari and co-researchers provide new insights

Source: VerticalNews Physics

May 5th, 2008

"Without imposing the trapping boundary conditions and only from within the very definition of area it is shown that the loop quantization of area manifests an unexpected degeneracy in area eigenvalues," researchers in Waterloo, Canada report.
"This could lead to a deeper understanding of the microscopic description of a quantum black hole," wrote M.H. Ansari and colleagues.

The researchers concluded: "If a certain number of semi-classically expected properties of black holes are imposed on a quantum surface its entropy coincides with the Bekenstein-Hawking entropy."

Ansari and colleagues published their study in NPB...

Classical and Quantum Geometry Conferences in 2009

Very High Energy Phenomena Feb 1-8 La Thuile 

http://moriond.in2p3.fr/J09/

Dark Matter Feb 2-6 CERN
http://indico.cern.ch/conferenceDisplay.py?confId=44160

Dark Matter Feb 9-11 Florence
http://ggi-www.fi.infn.it/index.php?p=events.inc&id=34

High-Freq Grav. Waves Feb 24-27 Huntsville

Dark Side of Gravity Mar 2-4 Florence
http://ggi-www.fi.infn.it//index.php?p=events.inc&id=40

New Directions in Cosmology Mar 16-20 Beijing tangxin@itp.ac.cn

Black Holes and LQG Mar 26-28 Valencia

 http://www.uv.es/bhlqg/

25th Pacific Coast Meeting Mar 27-28 Eugene
http://www.tapir.caltech.edu/pcgm25/index.html

Intermediate-Mass Black Holes Apr 1-3 Irvine
http://www.physics.uci.edu/IMBH/

Non-Gaussianities Apr 6-8 Tokyo
http://ipmu.jp/seminars/20090406-focusweek.html

Grav09 Apr 13-17 Cordoba
http://www.famaf.unc.edu.ar/~gdotti/grg/grav09/grav09.htm

BritGrav 9 Apr 15-16 Cardiff
http://www.astro.cf.ac.uk/research/gravity/?page=britgrav

Grishchuk Fest Apr 17 Cardiff
http://www.astro.cf.ac.uk/research/gravity/

NAM/JENAM Meeting Apr 20-23 Hatfield 

http://www.jenam2009.eu
(Grav Waves session 21)

Zeldovich 95th Apr 20-23 Minsk 

http://www.icranet.org/zeldovich

Relativity in Astrometry Apr 27-May 1 Virginia Beach
http://www.aas.org/divisions/meetings/iau/

Black Holes VII May 9-15 Banff
http://fermi.phys.ualberta.ca/~gravity/BH7

GW+HEN Workshop May 18-20 Paris 

http://www.gwhen-2009.org

Relativistic Astrophysics May 19-21 Atlanta
http://www.cra.gatech.edu/CenterConference/

Sobral Meeting May 26-29 Sobral secretariat@icranet.org

Chalonge Colloquoium May 28-29 Paris
http://chalonge.obspm.fr/colloque_ES2009.htm

Cosmological Magnetic Fields May 31-Jun 5 Ascona
http://theory.physics.unige.ch/CMF/

Standard Model of Universe Jun 4-5 Paris
http://chalonge.obspm.fr/colloque_ES2009.html

12th Eastern Gravity Meeting Jun 15-16 Rochester EGM2009@ccrg.rit.edu
http://ccrg.rit.edu/~EGM2009/

Mathematical Relativity Jun 18-19 Lisbon
http://www.math.ist.utl.pt/~jnatar/Mira/

21st Rencontres de Blois Jun 21-26 Blois
http://confs.obspm.fr/Blois2009/index.htm

Amaldi 8 Jun 21-26 New York amaldi8@gmail.com
http://www.amaldi8.org/

ICGA 9 Jun 28-Jul 1 Wuhan zhouzb@mail.hust.edu
http://ggg.hust.edu.cn/ICGA9/icga9.htm

Unity of the Universe Jun 29-Jul 1 Portsmouth
http://www.icg.port.ac.uk/sciama09/

Invisible Universe Jun 29-Jul 3 Paris
http://www.universe2009.obspm.fr

Marcel Grossmann MG12 Jul 12-18 Paris mg12@icra.it
http://www.icra.it/MG/mg12/

Chalonge: 13th Paris Cosmology Jul 23-25 Paris 

http://chalonge.obspm.fr

CosmoSTATS09 JUl 26-31 Ascona
http://www.itp.uzh.ch/cosmostats

Loops '09 Aug 2-8 Beijing

IAU General Assembly Aug 3-14 Rio de Janeiro

Neutron Stars: IAU JD Aug 3-5 Rio de Janeiro

IAU2009extreme@brera.inaf.it
http://www.brera.inaf.it/IAU2009extreme/index.html

NIJMEGEN09 Aug 18-28 Nijmegen 

http://nijmegen09.hef.kun.nl/

Grassmannian conference Sept 14-19 Szczecin
http://cosmo.fiz.univ.szczecin.pl

Challenges in Cosmology Sept 2-5 Talloires
http://cosmos.phy.tufts.edu/conference/

Space, Time and Beyond Oct 8-9 Golm
http://spacetimebeyond.aei.mpg.de/

Galileo - Xu Guangqi Oct 26-30 Shanghai
http://www.icranet.org/index.php?option=com_content&task=view&id=399&Itemid=686

Thanks to Malcolm MacCallum

Revewing a review on my work!

In Mathematical Reviews, all of my papers so far have been reviewed. One of the reviews is more extensive and after reading that I felt it could be a good idea if I have the chance to review this review in Gauge Invariance blog. I thank Maria Cristina Abbati for writing the original review.

Let me emphasize this review by no mean is to criticize the original review as it is fair in its real meaning. Moreover, this paper under discussion has been already published in NPB a year ago and the review was written recently. The review written for Math Rev is only a way to explain, publicize and partially simplify the contents of the paper briefly. Mathematical Reviews is a large archive of Physics and Math papers where these papers are reviewed again to be resorted.

The original review is in green color. The red words in between are not so to criticize something. The are marked red only to make my review easy to read and conclude. The red words do not oppose anything in the green lines, as they are mostly after one another.

In a previous paper [M. Ansari, NPB 783 (2007), no. 3, 179--212; MR2356347], the author gave an accurate description of the spectrum of the area operator as it is defined in loop quantum gravity.

He improved on previous results in the area, gave a new minimum value of the area in Planck's area unit, a_{min} = (3^0.5) * 2  \pi \gamma (where \gamma is the Immirzi parameter), and found a classification of the spectrum as a union of equidistant subsets which he called generations.

[I should correct the first part of the 2nd paragraph. In that article, I have not tried to give any new minimum value to the area.

In fact, this minimum value of area was reported by Abhay Ashtekar and Jerzy Lewandowski. They reported a spectrum of area in 1996. A few months later, Carlo Rovelli and his colleague reported the same spectrum of area using a completely different technique. Later on, Thomas Thiemann also studied this spectrum in more details and reported the same spectrum for a quantum of area.

And Yes!, in that paper I reported a new classification of the specrum of area, the so-called ladder symmetry. In fact there exists a universal formula for area that is way more compact that the one reported originally.]

This paper is complementary to the above paper and contains a detailed analysis of the degeneracy of the area's eigenvalues. The numerical results for the first hundred levels of the spectrum are summarized in scatterplots. Taking into account the generating properties, the degeneracy for a large area is estimated and results in \Omega(A) = g(a_{min}  ^N, where g(a_{min} is the degeneracy of the minimum value.

[Yes, I reported a hidden degeneracy as well as a ladder symmetry on area eigenvalues. 

However, one should not mistake this "numerical result" mentioned here as an approximation to an analytical result. In fact, there is no numerical result in this work. Everything has been reported in terms of theorems and they are exact result. Recently, Takashi Tamaki extended this classification of area eigenvalues in a different way. I will give it a brief review in later posts in gauge invariance.]

A kinematical entropy S is assigned to each area value, defined as the log of its degeneration. Assuming that A=Na_{min} for a large area, the formula S=A  log (  g(a_{min})  ) / a_{min} is obtained.

The formula is relevant when it is applied to the entropy of a non-rotating black hole and, compared with the Bekenstein-Hawking formula, determines the value of \gamma giving \gamma= log 3 / ( \pi 2^0.5  ) .

As the author remarks, he follows here the approach to black holes used by C. Rovelli (see the bibliography), where a surface in spacetime is initially considered and the expected properties of a black hole are imposed on its entropy at the semiclassical level. Another approach to black holes in loop quantum gravity was first studied by A. Ashtekar et al. [Phys. Rev. Lett. 80 (1998), no. 5, 904--907; MR1606489 (98k:83051)]. There, a boundary condition on spacetime was given at the classical level and the resulting Hamiltonian was quantized along the lines of loop quantization, giving a completely different kinematical space. In this approach the value for the Immirzi parameter is double Ansari's value.

[ The only notice to add here is that in the last sentence of above apargraph, one should note that this comparison is done in SO(3) group representations.]

A comparison of the two approaches is given by the author himself in the paper, but the question of the right black hole theory in loop quantum gravity and the value of the Immirzi parameter seems to be still open.

[ There is a main difference between the spin network black hole strategy, the one I studied in this paper, and the other opponent strategy that is called 'quantum isolated horizon picture.' 

The difference is that in the latter picture one needs to *believe* that different parts of a black hole horizon are distinguishable from one another. If this is not assumed, one does not get the entropy proportional to area, instead it will be proportional to A^0.5. This is a strange fact that honestly is true! This distinguish-ability is an additional assumption and since 1996 till now nobody showed why should we assume this when the states associated with the Chern-Simons horizon does not show that as a quantum fact to us. 

I neglectdiscussing the recent claims that the state of punctures are reported to be a sequence of punctures not a set of puncture. This assumption if is true generates an orderly difference between punctures, breaks a huge number of diffeomoerphism invariant class on the horizon and make each puncture distinguishable. However, there is no physical reason why should we prefer a sequence of punctures to a set of them. All of this seems to be passing a problem from distinguished states into an underlying diffeomorphism invariance breaking.

In the spin network black hole picture, which turns out to be a more quantum approach to understand a black hole, although the Thermodynamics of black hole and their evolutions have not been developed yet, but instead this picture does not suffer from the illness the other opponent suffers from. In other words, the entropy based on the degeneracy of spin network states is really proportional to the area A, and not A^0.5.

The reason is simple. The area operator when acts on the spin network states, it is in-sensitive to the completely tangential edges. The spin network states with different completely tangential edge states may belong to the same unification class of area eigenstates. However they may at the same time belong to completely different classes of other physical operators such as energy. As a consequence, any physical object that is described only by one parameter semi-classically, manifest area unification classes as a surface with distinguishable parts. In other words, two states with the same area that reside on a black hole horizon are distinguishable from one another only because their difference in their completely tangential edges, thus under the action of other operators they become recognizable. ]