What is Your Theory On Blackhole Radiation?

MSU Professor Chris Adami has found the solution to a long-standing problem with Stephen Hawking's black hole theory. In a groundbreaking study recently published in the journal Classical and Quantum Gravity, Adami found that various types of information, as specific as matter or particles, or as obscure as the contacts in your mobile phone or the contents of a secret diary, never disappear in the black hole to begin with, effectively solving the black hole information paradox of Hawking's theory. See: Plugging the Hole in Hawking's Black Hole Theory

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Why are Black Holes useful? Which are the quantum properties of space and time? And what happens to a Black Hole when it gets older? Assistant Professor Sabine Hossenfelder and Professor Lárus Thorlacius at Nordita talk about why they want to find answers to questions like these. See: Research Presentation: Quantum Gravity and Black Hole Physics Research at Nordita

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See Also:

• Black holes, quantum information, and the foundations of physics
• The black-hole information paradox, complementarity, and firewalls by Leonard Susskind 
•  Do Black Holes Destroy Information?

Quantum Mechanics and the Geometry of Spacetime

See:Colloquim January 30, 2014 - Quantum Mechanics and the Geometry of Spacetime

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Angels and Devils: MC Escher's use of Hyperbolic Space

See Also:

• Juan Maldacena's NYU colloquium on QM, GR

Entanglement and the Geometry of Spacetime

Theorists have forged a connection between wormholes in spacetime (above) and a quantum phenomenon called entanglement.

But how big an insight is this? It depends on whom you ask. Susskind and Maldacena note that in both papers, the original quantum particles reside in a space without gravity. In a simplified, gravity-free 3D model of our world, there can’t be any black holes or wormholes, Susskind adds, so the connection to a wormhole in a higher dimensional space is mere mathematical analogy. The wormhole and entanglement equivalence “only makes sense in a theory with gravity,” Susskind says. However, Karch and colleagues say that their calculations are an important first step toward verifying Maldacena and Susskind’s theory. Their toy model without gravity, Karch says, “gives a concrete realization of the idea that wormhole geometry and entanglement can be different manifestations of the same physical reality."A Link Between Wormholes and Quantum Entanglement

• Entanglement and Geometry of Spacetime
• Maldacena, Susskind: any entanglement is a wormhole of a sort

Note here about Issuu software in link above. I made a comment about this type of software with regard to document writing and appearance. For an open publishing format I am less then pleased that if you have a shared format and embedding program that allows you to embed articles and then does not do this, to me,  if you go a bit further into the program of Issuu then it's no more then a publishing ploy to get you to pay money for use of this type of publishing format. So while I started to use this program for document sharing I had to only provide the link to an interesting article to the ongoing saga of Maldacena and Susskind. I had to also substitute the main article by Maldacena,  with news story

See Also:

• A Black Hole Mystery Wrapped in a Firewall Paradox
• The black-hole information paradox, complementarity, and firewalls

Cool horizons for entangled black holes

Schwarzschild wormholes

General relativity contains solutions in which two distant black holes are connected through the interior via a wormhole, or Einstein-Rosen bridge. These solutions can be interpreted as maximally entangled states of two black holes that form a complex EPR pair. We suggest that similar bridges might be present for more general entangled states.
In the case of entangled black holes one can formulate versions of the AMPS(S) paradoxes and resolve them. This suggests possible resolutions of the firewall paradoxes for more general situations.Cool horizons for entangled black holes Juan Maldacena, Leonard Susskind

One of the most enjoyable and inspiring physics papers I have read in recent years is this one by Mark Van Raamsdonk. Building on earlier observations by Maldacena and by Ryu and Takayanagi. Van Raamsdonk proposed that quantum entanglement is the fundamental ingredient underlying spacetime geometry. Since my first encounter with this provocative paper, I have often mused that it might be a Good Thing for someone to take Van Raamsdonk’s idea really seriously. Entanglement=Wormholes preskill

See Also:

• Finding and abandoning incorrect general relativity lore

• Firewalls, Burning Brightly

Hmmmm...Pringles Potato Chip Still?

Solving quantum field theories via curved spacetimes by Igor R. Klebanov and Juan M. Maldacena

IN their figure 2. Hyperbolic space, and their comparative relation to the M.C.Escher's Circle Limit woodcut, Klebanov and Maldacena write, " but we have replaced Escher's interlocking fish with cows to remind readers of the physics joke about the spherical cow as an idealization of a real one. In anti-de Sitter/conformal theory correspondence, theorists have really found a hyperbolic cow."

Does Planck 2013 Data hurt the continuance of geometrical underpinnings?

The recent Planck satellite combined with earlier results eliminate a wide spectrum of more complex inflationary models and favor models with a single scalar field, as reported in the analysis of the collaboration. More important, though, is that all the simplest inflaton models are disfavored by the data while the surviving models -- namely, those with plateau-like potentials -- are problematic. We discuss how the restriction to plateau-like models leads to three independent problems: it exacerbates both the initial conditions problem and the multiverse-unpredictability problem and it creates a new difficulty which we call the inflationary "unlikeliness problem." Finally, we comment on problems reconciling inflation with a standard model Higgs, as suggested by recent LHC results. In sum, we find that recent experimental data disfavors all the best-motivated inflationary scenarios and introduces new, serious difficulties that cut to the core of the inflationary paradigm. Forthcoming searches for B-modes, non-Gaussianity and new particles should be decisive.See: Inflationary paradigm in trouble after Planck2013

 

X-ray: NASA/CXC/UNAM/Ioffe/D.Page,P.Shternin et al; Optical: NASA/STScI; Illustration: NASA/CXC/M.Weiss

See:

• The Pringles Potato Chip
• Spherical Cows and their X-ray Sources
• Chandra Images by Category: Supernovas & Supernova Remnants

A Conformal Field Theory Approach?

Using the anti–de Sitter/conformal field theory correspondence to relate fermionic quantum critical fields to a gravitational problem, we computed the spectral functions of fermions in the field theory. By increasing the fermion density away from the relativistic quantum critical point, a state emerges with all the features of the Fermi liquid. See:String Theory, Quantum Phase Transitions, and the Emergent Fermi Liquid

Spacetime in String Theory Dr. Gary Horowitz, UCSB

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Conformal Field Theory

A conformal field theory is a quantum field theory (or statistical mechanics model at the critical point) that is invariant under the conformal group. Conformal field theory is most often studied in two dimensions where there is a large group of local conformal transformations coming from holomorphic functions.

If your not sure what I mean,  have a look at what is happening on the surface of the sphere, as a means from which  a 2D description,  is describing the black hole in a 5d space. Have you seen this image before?

String theorists describe the physics of black holes in five-dimensional spacetime. They found that these five-dimensional objects provide a good approximation of the quark-gluon plasma in one fewer dimension, a relationship similar to the one between a three-dimensional object and its two-dimensional shadow. Image: SLAC National Accelerator Laboratory

Recreating the conditions present just after the Big Bang has given experimentalists a glimpse into how the universe formed. Now, scientists have begun to see striking similarities between the properties of the early universe and a theory that aims to unite gravity with quantum mechanics, a long-standing goal for physicists.

“Combining calculations from experiments and theories could help us capture some universal characteristic of nature,” said MIT theoretical physicist Krishna Rajagopal, who discussed these possibilities at the recent Quark Matter conference in Annecy, France.

One millionth of a second after the Big Bang, the universe was a hot, dense sea of freely roaming particles called quarks and gluons. As the universe rapidly cooled, the particles joined together to form protons and neutrons, and the unique state of matter known as quark-gluon plasma disappeared.See: String theory may hold answers about quark-gluon plasma

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Bekenstein Bound 

TWO UNIVERSES of different dimension and obeying disparate physical laws are rendered completely equivalent by the holographic principle. Theorists have demonstrated this principle mathematically for a specific type of five-dimensional spacetime ("anti–de Sitter") and its four-dimensional boundary. In effect, the 5-D universe is recorded like a hologram on the 4-D surface at its periphery. Superstring theory rules in the 5-D spacetime, but a so-called conformal field theory of point particles operates on the 4-D hologram. A black hole in the 5-D spacetime is equivalent to hot radiation on the hologram--for example, the hole and the radiation have the same entropy even though the physical origin of the entropy is completely different for each case. Although these two descriptions of the universe seem utterly unalike, no experiment could distinguish between them, even in principle. by Jacob D. Bekenstein

                                                                                ***

Consider any physical system, made of anything at all- let us call it, The Thing. We require only that The Thing can be enclosed within a finite boundary, which we shall call the Screen(Figure39). We would like to know as much as possible about The Thing. But we cannot touch it directly-we are restrictied to making measurements of it on The Screen. We may send any kind of radiation we like through The Screen, and record what ever changes result The Screen. The Bekenstein bound says that there is a general limit to how many yes/no questions we can answer about The Thing by making observations through The Screen that surrounds it. The number must be less then one quarter the area of The Screen, in Planck units. What if we ask more questions? The principle tells us that either of two things must happen. Either the area of the screen will increase, as a result of doing an experiment that ask questions beyond the limit; or the experiments we do that go beyond the limit will erase or invalidate, the answers to some of the previous questions. At no time can we know more about The thing than the limit, imposed by the area of the Screen.

Page 171 and 172 0f, Three Roads to Quantum Gravity by Lee Smolin

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Juan Maldacena:

The strings move in a five-dimensional curved space-time with a boundary. The boundary corresponds to the usual four dimensions, and the fifth dimension describes the motion away from this boundary into the interior of the curved space-time. In this five-dimensional space-time, there is a strong gravitational field pulling objects away from the boundary, and as a result time flows more slowly far away from the boundary than close to it. This also implies that an object that has a fixed proper size in the interior can appear to have a different size when viewed from the boundary (Fig. 1). Strings existing in the five-dimensional space-time can even look point-like when they are close to the boundary. Polchinski and Strassler1 show that when an energetic four-dimensional particle (such as an electron) is scattered from these strings (describing protons), the main contribution comes from a string that is close to the boundary and it is therefore seen as a point-like object. So a string-like interpretation of a proton is not at odds with the observation that there are point-like objects inside it.

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Holography encodes the information in a region of space onto a surface one dimension lower. It sees to be the property of gravity, as is shown by the fact that the area of th event horizon measures the number of internal states of a blackhole, holography would be a one-to-one correspondance between states in our four dimensional world and states in higher dimensions. From a positivist viewpoint, one cannot distinquish which discription is more fundamental.

Pg 198, The Universe in Nutshell, by Stephen Hawking

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In 1919, Kaluza sent Albert Einstein a preprint --- later published in 1921 --- that considered the extension of general relativity to five dimensions. He assumed that the 5-dimensional field equations were simply the higher-dimensional version of the vacuum Einstein equation, and that all the metric components were independent of the fifth coordinate. The later assumption came to be known as the cylinder condition. This resulted in something remarkable: the fifteen higher-dimension field equations naturally broke into a set of ten formulae governing a tensor field representing gravity, four describing a vector field representing electromagnetism, and one wave equation for a scalar field. Furthermore, if the scalar field was constant, the vector field equations were just Maxwell's equations in vacuo, and the tensor field equations were the 4-dimensional Einstein field equations sourced by an EM field. In one fell swoop, Kaluza had written down a single covariant field theory in five dimensions that yielded the four dimensional theories of general relativity and electromagnetism. Naturally, Einstein was very interested in this preprint .(sorry link now dead)

The Cross Over Point and Time Travel

One of the issues that is evoked by any faster-than-light transport is time paradoxes: causality violations and implications of time travel. As if the faster than light issue wasn’t tough enough, it is possible to construct elaborate scenarios where faster-than-light travel results in time travel. Time travel is considered far more impossible than light travel.

I mean sure how is it one can measure time in energy particulate views when it appears all smeared out? It is the collision process itself and what I see in nature as Cascading particles as microscopic blackholes created and then quickly dissipated as decay in those particle showers.

Seeing muon detections that tunnel, and find their way across the globe is something that is interesting, as we can now use them in measure, as to what passes through to what is fabricated there in the LHC, becomes an interesting new tool of climate change or even gravitational inclination in relativistic approaches.

Length contractions is a key word here in microscopic measure.

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Juan Martín Maldacena and Joseph Polchinski

Dr. Maldacena and Dr. Polchinski each gave brief lectures related to their work. Both included broad overviews of string theory basics, with Dr. Polchinski noting the importance of "thought experiments" to help physicists make advances in the field. He said that physicists are excited about future experiments using particle accelerators such as the Large Hadron Collider at CERN, where some of these "thought experiments" could be validated.

Dr. Maldacena, who was born in Buenos Aires, also spoke about ICTP's important influence on physics in Argentina, noting that many of his professors had spent time at the Centre. Dr. Maldacena himself has participated in ICTP training programmes and was a director of the Spring School on String Theory for four years.

The Dirac Medal is given in honour of P.A.M. Dirac, one of the greatest physicists of the 20th century and a staunch friend of ICTP, to scientists who have made significant contributions to physics. Recipients are announced annually on Dirac's birthday, 8 August. The Medallists also receive a prize of US $5,000.Noted physicists awarded Dirac Medal

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Juan Martín Maldacena, Institute for Advanced Study, Princeton
Joseph Polchinski, Kavli Institute for Theoretical Physics, University of California at Santa Barbara
and
Cumrun Vafa, Harvard University

Professors Maldacena, Polchinski and Vafa are being honored for their fundamental contributions to superstring theory. Their studies range from early work on orbifold compactifications, physics and mathematics of mirror symmetry, D-branes and black hole physics, as well as gauge theory-gravity correspondence. Their contributions in uncovering the strong-weak dualities between seemingly different string theories have enabled us to learn about regimes of quantum field theory which are not accessible to perturbative analysis. These profound achievements have helped us to address outstanding questions like confinement of quarks and QCD mass spectrum from a new perspective and have found applications in practical calculations in the fluid dynamics of quark gluon plasma.

The dualities have also led string theorists to conjecture that the five different superstring theories in ten space-time dimensions are manifestations of one underlying theory, yet undiscovered, which has been named the M-theory.See:Dirac Medalists 2008

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Another deep quantum mystery for which physicists have no answer has to do with "tunneling" -- the bizarre ability of particles to sometimes penetrate impenetrable barriers. This effect is not only well demonstrated; it is the basis of tunnel diodes and similar devices vital to modern electronic systems.

Tunneling is based on the fact that quantum theory is statistical in nature and deals with probabilities rather than specific predictions; there is no way to know in advance when a single radioactive atom will decay, for example.

The probabilistic nature of quantum events means that if a stream of particles encounters an obstacle, most of the particles will be stopped in their tracks but a few, conveyed by probability alone, will magically appear on the other side of the barrier. The process is called "tunneling," although the word in itself explains nothing.

Chiao's group at Berkeley, Dr. Aephraim M. Steinberg at the University of Toronto and others are investigating the strange properties of tunneling, which was one of the subjects explored last month by scientists attending the Nobel Symposium on quantum physics in Sweden.

"We find," Chiao said, "that a barrier placed in the path of a tunnelling particle does not slow it down. In fact, we detect particles on the other side of the barrier that have made the trip in less time than it would take the particle to traverse an equal distance without a barrier -- in other words, the tunnelling speed apparently greatly exceeds the speed of light. Moreover, if you increase the thickness of the barrier the tunnelling speed increases, as high as you please.

"This is another great mystery of quantum mechanics."Signal Travels Farther and Faster Than Light By MALCOLM W. BROWNE

You and I know it as a time machine. Physicists, on the other hand, call it a "closed timelike curve." Below, feast on the concepts and conjectures, the dialects and definitions that physicists rely on when musing about the possibility of time travel. If this list only whets your appetite for more, we recommend you have a gander at the book from which we excerpted this glossary: Black Holes and Time Warps: Einstein's Outrageous Legacy, by Kip S. Thorne (Norton, 1994).

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See Also:

Tunnelling in Faster then Light

Status of "Warp Drive"

Result of Effective Changes in the Cosmos

TimeSpeak

The Pringles Potato Chip

....a higher dimensional version of the Pringle's potato chip. Brian Greene, The Fabric of the Cosmos, pg 483, Para 2, line 29

Again I try remind good scientists that I have nothing to offer other then trying to keep pace with their thinking, and to find myself in world's of abstraction that I really find interesting. Of course, their metaphors too.

You see for me there are interesting correlations of thought that wake me up to the understanding of such abstract thinking, and what purposes it serves. I quote the Pringle Potato Chip to spell out the earlier realization of Maldacena, as well, the idea I have about, the Birth of Approximation. I was trying to tangle with such thoughts in a cosmological sense and here they speak to it in mathematical illustrations.

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IN their figure 2. Hyperbolic space, and their comparative relation to the M.C.Escher's Circle Limit woodcut, Klebanov and Maldacena write, " but we have replaced Escher's interlocking fish with cows to remind readers of the physics joke about the spherical cow as an idealization of a real one. In anti-de Sitter/conformal theory correspondence, theorists have really found a hyperbolic cow."

Click on image for larger version. See:Solving quantum field theories via curved spacetimes by Igor R. Klebanov and Juan M. Maldacena

Thank you, too "Just Learning" andDavid Berenstein for the information about the article above.

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See Also:

Spherical Cows and their X-ray Sources and related links in article

What is Happening at the Singularity?

WEll, some of the commentors like myself are not worth counting?:)Thanks for keeping it interesting Clifford of Asymptotia. I hope you won't mind the following quotes for consideration.( it was considered spam) so I reprint it here.

Quantum geometry differs in substantial ways from the classical geometry underlying general relativity. For instance, topology change (the "tearing" of space) is a sensible feature of quantum geometry even though, from a classical perspective, it involves singularities. As another example, two different classical spacetime geometries can give rise to identical physical implications, again at odds with conclusions based on classical general relativity. Brian Greene

Is there not some way presented by Susskind which can help one approach understanding of what is going on in the blackhole by incorporating his "thought experiment" in relation to the entanglement process?

So of course questions about "the horizon" are interesting.

Consider any physical system, made of anything at all- let us call it, The Thing. We require only that The Thing can be enclosed within a finite boundary, which we shall call the Screen(Figure39). We would like to know as much as possible about The Thing. But we cannot touch it directly-we are restricted to making measurements of it on The Screen. We may send any kind of radiation we like through The Screen, and record what ever changes result The Screen. The Bekenstein bound says that there is a general limit to how many yes/no questions we can answer about The Thing by making observations through The Screen that surrounds it. The number must be less then one quarter the area of The Screen, in Planck units. What if we ask more questions? The principle tells us that either of two things must happen. Either the area of the screen will increase, as a result of doing an experiment that ask questions beyond the limit; or the experiments we do that go beyond the limit will erase or invalidate, the answers to some of the previous questions. At no time can we know more about The thing than the limit, imposed by the area of the Screen. Page 171 and 172 0f, Three Roads to Quantum Gravity, by Lee Smolin

TWO UNIVERSES of different dimension and obeying disparate physical laws are rendered completely equivalent by the holographic principle. Theorists have demonstrated this principle mathematically for a specific type of five-dimensional spacetime ("anti–de Sitter") and its four-dimensional boundary. In effect, the 5-D universe is recorded like a hologram on the 4-D surface at its periphery. Superstring theory rules in the 5-D spacetime, but a so-called conformal field theory of point particles operates on the 4-D hologram. A black hole in the 5-D spacetime is equivalent to hot radiation on the hologram--for example, the hole and the radiation have the same entropy even though the physical origin of the entropy is completely different for each case. Although these two descriptions of the universe seem utterly unalike, no experiment could distinguish between them, even in principle. by Jacob D. Bekenstein

The old version of string theory, pre-1995, had these first two features. It includes quantum mechanics and gravity, but the kinds of things we could calculate were pretty limited. All of a sudden in 1995, we learned how to calculate things when the interactions are strong. Suddenly we understood a lot about the theory. And so figuring out how to compute the entropy of black holes became a really obvious challenge. I, for one, felt it was incumbent upon the theory to give us a solution to the problem of computing the entropy, or it wasn't the right theory. Of course we were all gratified that it did. Black Holes and Beyond: Harvard's Andrew Strominger on String Theory

So we have these diagrams and thought processes developed from individuals like Jacob D. Bekenstein to help us visualize what is taking place. Gives us key indicators of the valuation needed, in order to determine what maths are going to be used? In this case the subject of Conformal Field Theory makes itself known, for the thought process?

Holography encodes the information in a region of space onto a surface one dimension lower. It sees to be the property of gravity, as is shown by the fact that the area of th event horizon measures the number of internal states of a blackhole, holography would be a one-to-one correspondence between states in our four dimensional world and states in higher dimensions. From a positivist viewpoint, one cannot distinguish which description is more fundamental.Pg 198, The Universe in Nutshell, by Stephen Hawking

So we are given the label in which to speak about the holographic notions of what is being talked about in the case of the blackhole's horizon.


Campbell's Soup Can by Andy Warhol Exhibited in New York (USA), Leo Castelli Gallery

Spacetime in String Theory-Dr. Gary Horowitz, UCSB-Apr 20, 2005

This year marks the hundredth anniversary of Einstein's "miraculous year", 1905, when he formulated special relativity, and explained the origin of the black body spectrum and Brownian motion. In honor of this occasion, I will describe the modern view of spacetime. After reviewing the properties of spacetime in general relativity, I will provide an overview of the nature of spacetime emerging from string theory. This is radically different from relativity. At a perturbative level, the spacetime metric appears as ``coupling constants" in a two-dimensional quantum field theory. Nonperturbatively (with certain boundary conditions), spacetime is not fundamental but must be reconstructed from a holographic, dual theory. I will conclude with some recent ideas about the big bang arising from string theory.

The purpose of this note is to provide a possible answer to this question. Rather than the radical modification of quantum mechanics required for pure states to evolve into mixed states, we adopt a more mild modification. We propose that at the black hole singularity one needs to impose a unique final state boundary condition. More precisely, we have a unique final wavefunction for the interior of the black hole. Modifications of quantum mechanics where one imposes final state boundary conditions were considered in [6,7,8,9]. Here we are putting a final state boundary condition on part of the system, the interior of the black hole. This final boundary condition makes sure that no information is “absorbed” by the singularity.Gary T. Horowitz and Juan Maldacena,

See: Stringy Geometry

Self Evident Dimensional Perspective

Where a dictionary proceeds in a circular manner, defining a word by reference to another, the basic concepts of mathematics are infinitely closer to an indecomposable element", a kind of elementary particle" of thought with a minimal amount of ambiguity in their definition. Alain Connes

John Merryman in comment section:

Can they propose these dimensions as anything more then the copyrighted product of their own imagination and not loose control over the idea?

Okay I have a problem with the term "static."

I'll just give you an example of what I am thinking in relation to how we may perceive dimension and then of course, there is a mathematical interpretation of topological spaces that others are better qualified to speak on. How could there be such a geometrical interpretation at such quantum levels.

Is there such thing as "a breakdown of time" within the context of measure? It is my ignorance that separates me from the more educated here, yet it is not without wanting to understand, that I am pushing this point further.

Think about the following concept for a moment.

Savas Dimopoulos:

Here’s an analogy to understand this: imagine that our universe is a two-dimensional pool table, which you look down on from the third spatial dimension. When the billiard balls collide on the table, they scatter into new trajectories across the surface. But we also hear the click of sound as they impact: that’s collision energy being radiated into a third dimension above and beyond the surface. In this picture, the billiard balls are like protons and neutrons, and the sound wave behaves like the graviton.

Here we are given a new look into another dimension? A shift from what is euclidean, to what is now non-euclidean. It is really quite simple to understand "what Einstein did" when we now talk about gravity.




Juan Maldacena:

Strings existing in the five-dimensional space-time can even look point-like when they are close to the boundary. Polchinski and Strassler1 show that when an energetic four-dimensional particle (such as an electron) is scattered from these strings (describing protons), the main contribution comes from a string that is close to the boundary and it is therefore seen as a point-like object. So a string-like interpretation of a proton is not at odds with the observation that there are point-like objects inside it.

While it is abstract, the move to thinking in the new way is important while we are looking at the whole picture.

Albert Einstein

The surface of a marble table is spread out in front of me. I can get from any one point on this table to any other point by passing continuously from one point to a "neighboring" one, and repeating this process a (large) number of times, or, in other words, by going from point to point without executing "jumps." I am sure the reader will appreciate with sufficient clearness what I mean here by "neighbouring" and by "jumps" (if he is not too pedantic). We express this property of the surface by describing the latter as a continuum.Albert Einstein p. 83 of his Relativity: The Special and the General Theory

There are deeper philosophical questions here about being a realist and an anti-realist.?

René Thom

See:René Thom:René Thom (September 2, 1923 – October 25, 2002) was a French mathematician. He made his reputation as a topologist, moving on to aspects of what would be called singularity theory; he became celebrated for one aspect of this latter interest, his work as founder of catastrophe theory (later developed by Christopher Zeeman). He received the Fields Medal in 1958.



Photograph by Paul Halmos

Much emphasis has been placed during the past fifty years on the reconstruction of the geometric continuum from the natural integers, using the theory of Dedekind cuts or the completion of the field of rational numbers. Under the influence of axiomatic and bookish traditions, man perceived in discontinuity the first mathematical Being: "God created the integers and the rest is the work of man." This maxim spoken by the algebraist Kronecker reveals more about his past as a banker who grew rich through monetary speculation than about his philosophical insight. There is hardly any doubt that, from a psychological and, for the writer, ontological point of view, the geometric continuum is the primordial entity. If one has any consciousness at all, it is consciousness of time and space; geometric continuity is in some way inseparably bound to conscious thought.

The Radius of the Little Circle

Where a dictionary proceeds in a circular manner, defining a word by reference to another, the basic concepts of mathematics are infinitely closer to an indecomposable element", a kind of elementary particle" of thought with a minimal amount of ambiguity in their definition. Alain Connes

With such a statement, the "purity of thought," is speaking to a much more schematic understanding as we discuss the sociological thinking of mathematicians and the worlds they fantasize about? While deeper in reality the thought process(meditative) was engaged at a very subtle level, associated with the energy all pervasive.




Lee Smolin :

Another wonderful spin-off is that it turns out that the charge of the electron is related to the radius of the little circle. This should not be surprizing: If the electric field is just a manifestation of geometry, the electric charge should be, too.

THE TROUBLE WITH PHYSICS-Published by Houghton-Mifflin, Sep. 2006/Penguin (UK), Feb. 2007, Page 46

In "Star Shine," we start from a very large circle, but there is much to see from this circle, when we consider it's radius. We think "continuity" is somehow not involved, if we freeze this circle, and call it a discrete measure of the universe's age? Yet we know to well that the motivation of this universe from a "distant point" measure today entropically lives in the multitude of complexities?

Plato:

Model apprehension is part of the convergence that Lee Smolin and Brian Greene talk about, and without it, how could we look at nature and never consider that Einstein's world is a much more dynamical one then we had first learned from the lessons GR supplied, about gravity in our world?

On page 47 of the Trouble with Physics Lee goes on to say further down the page:

Lee Smolin:

Unfortunately, Einstein and the other enthusiasts were wrong. As with Nordstrom's theory, the idea of unification by adding a hidden dimension failed. It is important to understand why.

If all one had was the "cosmological view" one could be very happy about the way in which his observations have been deduced from the measures of our mechanical means, that we say that GR is very well suited.

Yet it has been through th efforts of reductionism that we have said, "hey there is indeed more depth to the views we have, that the mechanical measures are being tuned accordingly?"



Juan Maldacena:

The strings move in a five-dimensional curved space-time with a boundary. The boundary corresponds to the usual four dimensions, and the fifth dimension describes the motion away from this boundary into the interior of the curved space-time. In this five-dimensional space-time, there is a strong gravitational field pulling objects away from the boundary, and as a result time flows more slowly far away from the boundary than close to it. This also implies that an object that has a fixed proper size in the interior can appear to have a different size when viewed from the boundary (Fig. 1). Strings existing in the five-dimensional space-time can even look point-like when they are close to the boundary. Polchinski and Strassler1 show that when an energetic four-dimensional particle (such as an electron) is scattered from these strings (describing protons), the main contribution comes from a string that is close to the boundary and it is therefore seen as a point-like object. So a string-like interpretation of a proton is not at odds with the observation that there are point-like objects inside it.

While energy is being exemplified according to the nature of the particles we see in calorimetric design, what said that the energy here is not topologically smooth in it's orientations? Even we we move our views to the quantum regime.

Maybe having solved the "Continuum Hypothesis," we learned much about Einstein's inclinations?

The surface of a marble table is spread out in front of me. I can get from any one point on this table to any other point by passing continuously from one point to a "neighboring" one, and repeating this process a (large) number of times, or, in other words, by going from point to point without executing "jumps." I am sure the reader will appreciate with sufficient clearness what I mean here by "neighbouring" and by "jumps" (if he is not too pedantic). We express this property of the surface by describing the latter as a continuum.Albert Einstein p. 83 of his Relativity: The Special and the General Theory

Even Einstein had to add the "extra dimension" so we understood what non-euclidean views meant in a geometrical sense. I again refer here to Klein's Ordering of Geometries so one understands the schematics and evolution of that geometry.

Concepts of the Fifth Dimension

"Yet I exist in the hope that these memoirs, in some manner, I know not how, may find their way to the minds of humanity in Some Dimensionality, and may stir up a race of rebels who shall refuse to be confined to limited Dimensionality." from Flatland, by E. A. Abbott

Oskar Klein September 15, 1894 - February 5, 1977

Dealing With a 5D World

A black hole is an object so massive that even light cannot escape from it. This requires the idea of a gravitational mass for a photon, which then allows the calculation of an escape energy for an object of that mass. When the escape energy is equal to the photon energy, the implication is that the object is a "black hole."

Herein, I also make the assumption:

The Spacetime Fabric, "is" the Fifth dimension.

Now of course, how do such assumptions make their way into my thinking and visualizations that I do? The seeing, of what mathematics and it's symbology had done for those who might see the geometry of expression, as a very vital way of thinking in the abstract world of mind, analogous, to the computer screen in front of us?


Juan Maldacena:

The strings move in a five-dimensional curved space-time with a boundary. The boundary corresponds to the usual four dimensions, and the fifth dimension describes the motion away from this boundary into the interior of the curved space-time. In this five-dimensional space-time, there is a strong gravitational field pulling objects away from the boundary, and as a result time flows more slowly far away from the boundary than close to it. This also implies that an object that has a fixed proper size in the interior can appear to have a different size when viewed from the boundary (Fig. 1). Strings existing in the five-dimensional space-time can even look point-like when they are close to the boundary. Polchinski and Strassler1 show that when an energetic four-dimensional particle (such as an electron) is scattered from these strings (describing protons), the main contribution comes from a string that is close to the boundary and it is therefore seen as a point-like object. So a string-like interpretation of a proton is not at odds with the observation that there are point-like objects inside it.

(Wikipedia 23 April 2006)

Similarly, in general relativity, the fourth dimension is manifested in observable three dimensions as the curvature of path of a moving infinitesimal (test) particle. 't Hooft has speculated that the fifth dimension is really the spacetime fabric.

Linked paragraph above was pointed out to a link you to further thoughts on this. It was a strange revelation of sorts to think that such a process could lead you to such thinking, as well, as leading one to understand how General Relativity becomes a result of of String theory.

It just made so much sense as I watched this developement take place in this geometrical extension of thought, that to a beginning, from a point to a line to a plane, was raised in mind, as a short cut to the brane world understandings. I really do not undertsand how I made this jump, but never the less, it took me to a fifth dimensional referencing.



The work of Banchoff helped in this understanding. In using image production, our 2d computer screens, as example, shows the work we are doing in the abstract space of mind.

While I am still ever the student, such thinking moved from the ideas of General Relativity, and it's geoemtrical nature, moves one into the dynamical regions of thought. Held, in regards to those curvatures. I just tend to see them in this way after understanding the "geometrical nature." So too, the undertanding of General Relativity means, and in this assumption, "gravity" becomes the terminology that I see in the dynamcis of that universe.

Can I help seeing the thought of humanity so capable in the mind, to relate choices to the heart and the feather weighting truth, that I also had come to see the gravity of that situation? IN such thoughts, Einsteins analogy of the Pretty girl always come to mind. It was a conceptual leap of sorts, as well as beautifully laid out model of GR as to our understanding in terms of what gravity means.

From strong to weak, and all the understanding of the place, where a flat plane of which no gravity exists, is a place where such transitions take place in my mind. Is this true or not? The very thinking of brane developement lead me to think in a 2 dimensional framework, yet I am well aware of the fifth dimensional views that this framework supplies. Is it wrong? I would have to rely on competent readers of the Brane world to have them say ye or nay, as to the thoughts being portrayed here.

(Wikipedia 23 April 2006)

In physics and mathematics, a sequence of N numbers can be understood to represent a location in an N-dimensional space. When N=5, one of these numbers is sometimes colloquially called the fifth dimension. This usage may occur in casual discussions about the fourth dimension, which, in the context of physics, refers to time, coming after the first three spatial dimensions (up/down, left/right and forwards/backwards). Abstract five-dimensional space occurs frequently in mathematics, and is a perfectly legitimate construct. Whether or not the real universe in which we live is somehow five-dimensional is a topic that is debated and explored in several branches of physics, including astrophysics and particle physics.

Lisa Randall:

My most recent research is about extra dimensions of space. Remarkably, we can potentially "see" or "observe" evidence of extra dimensions. But we won't reach out and touch those dimensions with our fingertips or see them with our eyes. The evidence will consist of heavy particles known as Kaluza-Klein modes that travel in extra-dimensional space. If our theories correctly describe the world, there will be a precise enough link between such particles (which will be experimentally observed) and extra dimensions to establish the existence of extra dimensions. Dangling Particles,By LISA RANDALL, Published: September 18, 2005 New York Yimes

The extensions beyond what we had always taken for meaning as "seeing," is the undertanding that all 3 space coordinated directions with time, are embedded in some "design" beyond that frame of reference held to General Relativity. If it wasn't, how could anything working beyond this, be found as a coordinated result?

(Wikipedia 23 April 2006)











Figure 2. Clebsch's Diagonal Surface: Wonderful

Pre-Big Bang: Ekpyrotic and Cyclical

Juan Maldacena (Princeton IAS)

Singularities similar to Singularities of some blackholes in Ads₃->suggest no information Transfer

Laying the Foundation with Respect

It is most certain that at this point the public would have been left behind, so is there a way to bring perspective at this point on where you are now?

I recognize the generalization and roads that lead to blackhole as a basis for considerations. What would draw ones atyemtion to this horizon. Lee Smolin in his book gave adequate discription that I just pointed out here.

Three Roads to Quantum Gravity, by Lee Smolin, pg 171


I know it might seem that if this conversation is now highlighting the intricacies of blackhole dynamics, then what exactly are you doing?



By giving a visual map of the Bekenstein Bound this help to direct my attention to the mapping that had been going on theorectically here.

Mine would definitiely be generalizations, but work by others lead to deeper insights.

Conformal Field Theory

A conformal field theory is a quantum field theory (or statistical mechanics model at the critical point) that is invariant under the conformal group. Conformal field theory is most often studied in two dimensions where there is a large group of local conformal transformations coming from holomorphic functions.

So what "tidbits" had already been out there then that would help.


Black Holes and Beyond:
Harvard's Andrew Strominger on String Theory

Quantum Micostates?

The old version of string theory, pre-1995, had these first two features. It includes quantum mechanics and gravity, but the kinds of things we could calculate were pretty limited. All of a sudden in 1995, we learned how to calculate things when the interactions are strong. Suddenly we understood a lot about the theory. And so figuring out how to compute the entropy of black holes became a really obvious challenge. I, for one, felt it was incumbent upon the theory to give us a solution to the problem of computing the entropy, or it wasn't the right theory. Of course we were all gratified that it did.

While this is a past issue for most of you it is leading in the direction you are talking I assume.


Holography encodes the information in a region of space onto a surface one dimension lower. It sees to be the property of gravity, as is shown by the fact that the area of the event horizon measures the number of internal states of a blackhole, holography would be a one-to-one correspondance between states in our four dimensional world and states in higher dimensions. From a positivist viewpoint, one cannot distinquish which discription is more fundamental.

Pg 198, The Universe in Nutshell, by Stephen Hawking

Gary T. Horowitz and Juan Maldacena,

The purpose of this note is to provide a possible answer to this question. Rather than the radical modification of quantum mechanics required for pure states to evolve into mixed states, we adopt a more mild modification. We propose that at the black hole singularity one needs to impose a unique final state boundary condition. More precisely, we have a unique final wavefunction for the interior of the black hole. Modifications of quantum mechanics where one imposes final state boundary conditions were considered in [6,7,8,9]. Here we are putting a final state boundary condition on part of the system, the interior of the black hole. This final boundary condition makes sure that no information is “absorbed” by the singularity.

While there is no "apparent relationship(?)" between microstate blackhole production and blackholes what would make one think that particle collsions can be written as dual blackholes?

The Fifth Dimension, is the Spacetime Fabric

Perhaps Quantum Gravity can be Handled by thoroughly reconsidering Quantum Mechanics itself? by Gerard t' Hooft

I was attracted to Nigel Cook's statement on Peter Woits blog entitled, "Panel Discussion Video" by the quote of his taken here below. What immediately struck my mind, was the Bekenstein Bound and how "temperature" would have been seen from that perspective.

Bekenstein Bound:

Superstring theory rules in the 5-D spacetime, but a so-called conformal field theory of point particles operates on the 4-D hologram. A black hole in the 5-D spacetime is equivalent to hot radiation on the hologram--for example, the hole and the radiation have the same entropy even though the physical origin of the entropy is completely different for each case.

Lee Smolin post given at Peter Woit's site was a ressurrection of "Three Roads to Quantum Gravity", and I like the fact that he wants cohesion amongst physicists and theoriticians alike. But if stauchly held to any position, then you have divisive comment about the ways in which to approach things. It can't be helped. But asking for more clarity this might be a good thing, and a approach by Lubos to qualify the string theorist position.

Lubos Motl:

The holographic conjecture, based on the Bekenstein's bounds and the Bekenstein-Hawking entropy of the black hole,has been first proposed by Gerard 't Hooft and discussed in more detail by Lenny Susskind:

But before consider Nigel's comment, I wanted to quote something from Lee Smolin.

Consider any physical system, made of anything at all- let us call it, The Thing. We require only that The Thing can be enclosed within a finite boundary, which we shall call the Screen(Figure39). We would like to know as much as possible about The Thing. But we cannot touch it directly-we are restrictied to making measurements of it on The Screen. We may send any kind of radiation we like through The Screen, and record what ever changes result The Screen. The Bekenstein bound says that there is a general limit to how many yes/no questions we can answer about The Thing by making observations through The Screen that surrounds it. The number must be less then one quarter the area of The Screen, in Planck units. What if we ask more questions? The principle tells us that either of two things must happen. Either the area of the screen will increase, as a result of doing an experiment that ask questions beyond the limit; or the experiments we do that go beyond the limit will erase or invalidate, the answers to some of the previous questions. At no time can we know more about The thing than the limit, imposed by the area of the Screen.

Page 171 and 172 0f, Three Roads to Quantum Gravity by Lee Smolin

Nigel Cook:

'Caloric’, fluid heat theory, eventually gave way to two separate mechanisms, kinetic theory and radiation. This was after Prevost in 1792 suggested constant temperature is a dynamic system, with emission in equilibrium with the reception of energy.

Yet I understand this call for bringing a string theorist into the fold of Lee's, but I would remind him, that such cosmological approaches are well on their way with the course ISCAP set for themselves and how comsological realization, are still important features that string theory would like to get a hold of.



Juan Maldacena:

The strings move in a five-dimensional curved space-time with a boundary. The boundary corresponds to the usual four dimensions, and the fifth dimension describes the motion away from this boundary into the interior of the curved space-time. In this five-dimensional space-time, there is a strong gravitational field pulling objects away from the boundary, and as a result time flows more slowly far away from the boundary than close to it. This also implies that an object that has a fixed proper size in the interior can appear to have a different size when viewed from the boundary (Fig. 1). Strings existing in the five-dimensional space-time can even look point-like when they are close to the boundary. Polchinski and Strassler1 show that when an energetic four-dimensional particle (such as an electron) is scattered from these strings (describing protons), the main contribution comes from a string that is close to the boundary and it is therefore seen as a point-like object. So a string-like interpretation of a proton is not at odds with the observation that there are point-like objects inside it.

The Black Hole Final State

Mathematics is not the rigid and rigidity-producing schema that the layman thinks it is; rather, in it we find ourselves at that meeting point of constraint and freedom that is the very essence of human nature.

- Hermann Weyl

It was a nice vacation and now being back, I see Lubos is clarifying some issues here for us to consider.

"Lubos Motl:

However, Hawking's semiclassical calculation leads to an exactly (piecewise) thermal final state. Such a mixed state in the far future violates unitarity - pure states cannot evolve into mixed states unitarily - and it destroys the initial information about the collapsed objects which is why we call it "information loss puzzle". A tension with quantum mechanics emerges.

The Gepner point demonstrates greater potential recognition of the brane world understandings and two dimensional views from a five dimenisonal developmentment for those who do not like such abstract adventures P.P. Cook helps to enlighten us on this subject.

So have I done justice to the developing perspective, that we are now ready to take what what demonstrated, and move it to a greater format for those who will lead us laymen through the world of the abstract mathematics? To help us enjoy what was mathematically unenduring for those not gifted to see the B field manifestaion, is a continuance of what we like to engage at higher dimensional perspectives. And really, it is all about imagery is it not?




Lee Smolin:

It was worry about the possibility that string theory would lead to the present situation, which Susskind has so ably described in his recent papers, that led me to invent the Cosmological Natural Selection [CNS] idea and to write my first book. My motive, then as now, is to prevent a split in the community of theoretical physicists in which different groups of smart people believe different things, with no recourse to come to consensus by rational argument from the evidence.

You must understand the state of thinking and dualistic nature that continues to force minds to engage the process, and this quest for wholeness, between two thoughts that are part and parcel of the same thing? Relativity and Quantum Nature. The larger circle is RElativity, and the smaller, the quantum nature. LQG and STring work from their respective positions.

So do we select the basis for this model, and find that LQG and Strings are formulated on principals embedded in association with the blackhole topic? This throws light back again on a topic that has been shared more then once by such trends in thinking as Lubos exemplfies for us, and again directs our thoughts towards Lenny Susskind and Lee Smolin, in contrast to each other.

I see people are teaming up appropriately, such as Cosmic Variance, and this of course has already been lead by Lubos and Peter's contrast to each other. Whether some like to speculate on co-joining for such comparsions on the validity of strings, versus no strings approach, as resolutions, had already been developed while we see this new means to develope, much as Brain Greene and others in ISCAP foundations principals.

So of course onward and forward, we push the topic and the expertise for the layperson like me, that we see and continue to find, developmental processes appropriately gathering for future thoughts shared? Again too, we see Quantum Diaries has indeed served it's purpose more then once in what John Ellis and other's have shared, have open the doorway to how we see such developmental attitudes expanding in contrast to the larger circle of possibilties.

See John's latest entree and for me, hitting big objects and particle collisions still open the mind for the natural cosmic interactive processes ongoing in nature around us.

Anyway back to the title of this post. I have some thinking here to do.

Gary T. Horowitz1 and Juan Maldacena,2

The purpose of this note is to provide a possible answer to this question. Rather than the radical modification of quantum mechanics required for pure states to evolve into mixed states, we adopt a more mild modification. We propose that at the black hole singularity one needs to impose a unique final state boundary condition. More precisely, we have a unique final wavefunction for the interior of the black hole. Modifications of quantum mechanics where one imposes final state boundary conditions were considered in [6,7,8,9]. Here we are putting a final state boundary condition on part of the system, the interior of the black hole. This final boundary condition makes sure that no information is “absorbed” by the singularity.

If indeed we started to think about the point on the brane then what kind of simplification can be drawn so that those less enclined to such abstract thinking could find a greater potential to that dimensionnal thinking?

(a) Compactifying a 3-D universe with two space dimensions and one time dimension. This is a simplification of the 5-D space­time considered by Theodor Kaluza and Oskar Klein. (b) The Lorentz symmetry of the large dimension is broken by the compactification and all that remains is 2-D space plus the U(1) symmetry represented by the arrow. (c) On large scales we see only a 2-D universe (one space plus one time dimension) with the "internal" U(1) symmetry of electromagnetism.

Here such thoughts begin to form around the idealization of computer graphics imagery developed and leading in this idealization of this two dimensional screen. We see where the likes of Thomas Banchoff demonstrate where such new roads to the developing insight ot this imagery can be seen in Smolins views of the Bekenstein Bound, that we we now understand a greater potential exists in how we view the screen, and what is being described in the blackhole horizon?



Let me show this image again, for greater clarity of what I mean.

Quantum Gravity

I've put together links for reference on the particular subject titled. If someone has others that they would like to add, please do. I will be placing a permanent link on the sidebar for reference. Hope its useful.

List of quantum gravity researchers

• Jan Ambjørn: Expert on dynamical triangulations who helped develop the causal dynamical triangulations approach to quantum gravity.
• Giovanni Amelino-Camelia: Physicist who developed the idea of Doubly special relativity, and founded Quantum-Gravity phenomenology.
• Abhay Ashtekar: Inventor of the Ashtekar variables, one of the founders of loop quantum gravity.
• John Baez: Mathematical physicist who introduced the notion of spin foam in loop quantum gravity (a term originally introduced by Wheeler).
• John W. Barrett: Mathematical physicist who helped develop the Barrett-Crane model of quantum gravity.
• Julian Barbour: Philosopher and author of The End of Time, Absolute or Relative Motion?: The Discovery of Dynamics.
• Martin Bojowald: Physicist who developed the application of loop quantum gravity to cosmology.
• Steve Carlip: Expert on 3-dimensional quantum gravity.
• Louis Crane: Mathematician who helped develop the Barrett-Crane model of quantum gravity.
• Fay Dowker: Physicist working on causal sets as well as the interpretation of quantum mechanics.
• David Finkelstein: Physicist who has contributed much quantum relativity and the logical foundations of QR.
• Charles Francis: Mathematician who has developed a background-independent model of physics called Relational Quantum Gravity.
• Rodolfo Gambini: Physicist who helped introduce loop quantum gravity; coauthor of Loops, Knots, Gauge Theories and Quantum Gravity.
• Gary Gibbons: Physicist who has done important work on black holes.
• Brian Greene: Physicist who is considered one of the world's foremost string theorists.
• James Hartle: Physicist who helped develop the Hartle-Hawking wavefunction for the universe.
• Stephen Hawking: Leading physicist, expert on black holes and discoverer of Hawking radiation who helped develop the Hartle-Hawking wavefunction for the universe.
• Friedrich W. Hehl: Physicist who developed the metric-affine gauge theory of gravity and published a Physics Reports review article about this subject.
• Christopher Isham: Physicist who focuses on conceptual problems in quantum gravity.
• Mark Israelit Physicist who worked on torsional Weyl-Dirac electrodynamics, quantum gravity and quantum cosmology (cosmic egg model, together with Nathan Rosen).
• Ted Jacobson: Physicist who helped develop loop quantum gravity.
• John Klauder: Physicist. Proponent of the theory called Affine Quantum Gravity.
• Renate Loll: Physicist who worked on loop quantum gravity and more recently helped develop the causal dynamical triangulations approach to quantum gravity.
• Robert B. Mann: Physicist who works on "Lineal" gravity i.e. gravity in lower dimensions and alternate theories within quantum field theory.
• Fotini Markopoulou-Kalamara: Physicist who works on loop quantum gravity and spin network models that take causality into account.
• Herman Nikolai: Physicist who works on quantum gravity and investigates Kac-Moody algebras as a candidate symmetry for supergravity theories and M-theory.
• Roger Penrose: Mathematical physicist who invented spin networks and twistor theory.
• Jorge Pullin: Physicist who helped develop loop quantum gravity, coauthor of Loops, Knots, Gauge Theories and Quantum Gravity.
• Carlo Rovelli: One of the founders and major contributors to loop quantum gravity.
• Lee Smolin: One of the founders and major contributors to loop quantum gravity.
• Rafael Sorkin: Physicist, primary proponent of the causal set approach to quantum gravity.
• Andrew Strominger: Physicist who works on string theory.
• Thomas Thiemann: Physicist who works on loop quantum gravity.
• Frank J. Tipler: Mathematical physicist who maintains in a 2005 paper^[1] published in Reports on Progress in Physics that the correct quantum gravity theory has existed since 1962, first discovered by Richard Feynman in that year, and independently discovered by others. Intrinsic to this theory of quantum gravity are certain boundary conditions, which includes an Omega Point final cosmological singularity.
• Bill Unruh: Canadian physicist engaged in the study of semiclassical gravity and responsible for the discovery of the so-called Unruh effect.
• Robert Wald: Leading physicist in the field of quantum field theory in curved spacetime.
• Anzhong Wang: Physicist, major contributor to Horava-Lifshitz gravity; String theory and applications to cosmology.
• Edward Witten: Leading mathematical physicist, does research in string theory and M-theory.
• Richard Woodard: Physicist, major contributor to canonical, perturbative, and finite infrared quantum gravity; applications to cosmology.

List of loop quantum gravity researchers

• Abhay Ashtekar, Pennsylvania State University, USA
• John Baez, University of California, Riverside, USA
• John W. Barrett, University of Nottingham, UK
• Sundance Bilson-Thompson, Perimeter Institute for Theoretical Physics, Canada
• Martin Bojowald, Pennsylvania State University, USA
• Steve Carlip, University of California, Davis, USA
• Alejandro Corichi, National Autonomous University of Mexico, Mexico
• Olaf Dreyer, MIT, USA
• Laurent Freidel, Perimeter Institute for Theoretical Physics, Canada
• Rodolfo Gambini, Universidad de Montevideo, Uruguay
• Christopher Isham, Imperial College London, UK
• Renate Loll, Utrecht University, The Netherlands
• Fotini Markopoulou-Kalamara, Perimeter Institute for Theoretical Physics, Canada
• Donald Marolf, University of California, Santa Barbara, USA
• Jorge Pullin, Louisiana State University, USA
• Carlo Rovelli, Centre de Physique Theorique, Marseille, France
• Lee Smolin, Perimeter Institute for Theoretical Physics, Canada

String Theorist People

• Mina Aganagic
• Ofer Aharony
• John Randolph Sides
• Nima Arkani-Hamed
• Michael Francis Atiyah
• Igor Bandos
• Tom Banks
• Katrin Becker
• Melanie Becker
• David Berenstein
• Gerald Cleaver
• Mirjam Cvetic
• Atish Dabholkar
• Sumit R. Das
• Erik D'Hoker
• Robbert Dijkgraaf
• Jacques Distler
• Michael Douglas
• Michael Duff
• Sergio Ferrara
• Willy Fischler
• Daniel Friedan
• Davide Gaiotto
• Ori Ganor
• E. Gava
• Rajesh Gopakumar
• Michael Green
• Brian Greene
• David Gross
• Steven Gubser
• Sergei Gukov
• Amihay Hanany
• Jeffrey Harvey
• Petr Horava
• Gary Gibbons
• Michio Kaku
• Renata Kallosh
• Theodor Kaluza
• Anton Kapustin
• Elias Kiritsis
• Igor Klebanov
• Oskar Klein
• Miao Li
• Hong Liu
• Oleg Lunin
• Juan Maldacena
• Gautam Mandal
• Donald Marolf
• Emil Martinec
• Samir Mathur
• Shiraz Minwalla
• Gregory Moore
• Lubos Motl
• Sunil Mukhi
• Robert Myers
• Asad Naqvi
• K.S. Narain
• Horatiu Nastase
• Nikita Nekrasov
• André Neveu
• Dimitri Nanopoulos
• Holger Bech Nielsen
• Peter van Nieuwenhuizen
• Hirosi Ooguri
• Joseph Polchinski
• Alexander Polyakov
• Arvind Rajaraman
• Lisa Randall
• Seifallah Randjbar-Daemi
• Leonardo Rastelli
• Martin Rocek
• John H. Schwarz
• Nathan Seiberg
• Ashoke Sen
• Samson Shatashvili
• Steve Shenker
• Warren Siegel
• Eva Silverstein
• Link Starbureiy
• Matthias Staudacher
• Andrew Strominger
• Leonard Susskind
• Paul Townsend
• Sandip Trivedi
• Cumrun Vafa
• Gabriele Veneziano
• Erik Verlinde
• Herman Verlinde
• Spenta Wadia
• Edward Witten
• Xi Yin
• Tamiaki Yoneya
• Alexander Zamolodchikov
• Alexei Zamolodchikov
• Barton Zwiebach

Quantum Gravity quote

A pessimist might say that combining string theory and loop quantum gravity is like combining epicycles and aether.

(John Baez, TWF281)

What is Quantum Gravity?

Moderator: Stephen Shenker, Panelists: Abhay Ashtekar, Juan Maldacena, Leonard Susskind, Gerard 't Hooft, Cumrun Vafa

Jan Ambjørn

Kostas  Anagnostopoulos

John Baez

Julian Barbour

Chris  Isham

Ted  Jacobson

Renate  Loll

Fotini Markopoulou Kalamara at Penn
State University and Albert
Einstein Institute

Carlo  Rovelli

CGPG: Center  for Gravitational Physics and Geometry

High-Energy Theory  Group at The Niels Bohr Institute

Imperial College  Theoretical Physics Group

The Max Planck Institute for Gravitational Physics (Albert  Einstein Institute)

Penn State Physics Department

Perimeter Institute for Theoretical Physics

String theory

Loop quantum gravity of Smolin and Rovelli

Noncommutative geometry of Alain Connes

Twistor theory of Roger Penrose

Abhay Ashtekar -- Author of Ashtekar variables, he is one of the founders of loop quantum gravity.

John Baez -- Mathematical physicist.

Julian Barbour -- Author of The End of Time, Absolute or Relative Motion? and The Discovery of Dynamics.

Martin Bojowald --

Louis Crane -- Theorist.

Rodolfo Gambini -- Author of Loops, Knots, Gauge Theories and Quantum Gravity.

Brian Greene -- Physicist who is considered one of the world's foremost string theorists.

Stephen Hawking -- Leading theoretical physicists.

Peter Higgs -- Proposed the 1960's theory of broken symmetry in electroweak theory,

Christopher Isham -- Theoretical physicist.

Michio Kaku -- Theoretical physicist with significant contribution to the string field theory.

Fotini Markopoulou-Kalamara -- Theoretical physicist interested in foundational mathematics and quantum mechanics

Roger Penrose -- Mathematical physicist and imade the invention of spin networks.

Jorge Pullin -- Theoretical physicist.

Carlo Rovelli -- Obtained, with Lee Smolin, an explicit basis of states of quantum geometry.

Lee Smolin -- Theoretical physicist who has made major contributions to loop quantum gravity.

Andrew Strominger -- Theoretical physicist who works on string theory

Thomas Thiemann -- Researcher.

Edward Witten -- Mathematical physicist who does research in M-theory

Centauro event

String theory

M-theory

Loop Quantum Gravity by Carlo Rovelli

http://gravity.psu.edu/online/Html/Seminars/Fall1999/Amelino-Camelia/Slides/s01.html

http://www.thp.univie.ac.at/alt/local/gravity/links.html

http://www.theory.caltech.edu/people/patricia/test/Einstein3.htmlSolving Relativity in Three Dimensions.

http://www.tsolkas.gr/english/document1/document1.html

http://www.pitt.edu/~wbcurry/index.html

http://newolder.netfirms.com/upper%20f%20for%20em%20radiation.htm

http://www.parcellular.fsnet.co.uk

http://www.unifiedftheory.com

http://www.damtp.cam.ac.uk/user/gr/public/qg_home.html

http://www.maths.nott.ac.uk/personal/jwb/qg.html

http://www.npac.syr.edu/users/paulc/physics/surfaces.html

http://www.npac.syr.edu/PROJECTS/PUB/paulc/physics/surfaces.html

http://www.physics.nyu.edu/faculty/sokal/transgress_v2/transgress_v2.html

http://graham.main.nc.us/~bhammel/FCCR/qg.html

http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/980420b.html

http://www.madsci.org/posts/archives/may96/831205229.Ph.r.html

http://zebu.uoregon.edu/~js/glossary/quantum_gravity.html

http://penlee.inje.ac.kr/research/black.htm Quantum Gravity and Black Hole Related Published Articles...

http://wwwgro.unh.edu/compton5/submitted_abstracts/A005_Kaaret.html

http://www.zebu.uoregon.edu/~js/glossary/quantum_gravity.html

http://www.fervor.demon.co.uk/qgravity.htm

http://newton.skku.ac.kr/research-interest/k-research-interest.html

http://www.nd.edu/~chemlib/journals/cqg.htm

http://www.maths.nott.ac.uk/personal/jwb/

http://www.damtp.cam.ac.uk/user/gr/public/bh_hawk.html

http://suhep.phy.syr.edu/research/randomsurfaces/

http://www.phys.psu.edu/~beetle/Phys/tqft.html

http://www.maths.nott.ac.uk/personal/jwb/pg.html

http://aeneas.ps.uci.edu/aeneas/benchqgmpi.html

http://www.lib.msu.edu/dbases/item/000362.html

http://www.deepspace.ucsb.edu/research/grqg.html

http://www.pitt.edu/~wbcurry/qg.html

http://physics.syr.edu/research/relativity/rel-fac.html

http://www.maths.nottingham.ac.uk/personal/jwb/qg.4d.html

http://www.ps.uci.edu/physics/hamber.html

http://simscience.org/membranes/advanced/essay/gravity_simulation1.html

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What is Quantum Gravity

Finally, string theory started out as a generalization of quantum field theory where instead of point particles, string-like objects propagate in a fixed spacetime background. Although string theory had its origins in the study of quark confinement and not of quantum gravity, it was soon discovered that the string spectrum contains the graviton, and that "condensation" of certain vibration modes of strings is equivalent to a modification of the original background.

LQG does not have this feature to describe point particles, where a one dimensional string includes gravity.

According to Wikipedia:

1.loop quantum gravity makes too many assumptions
2. according to the logic of the renormalization group, the Einstein-Hilbert action is just an effective description at long distances

3. loop quantum gravity is not a predictive theory

4. loop quantum gravity has not offered any non-trivial self-consistency checks

5. loop quantum gravity is isolated from particle physics

6. loop quantum gravity does not guarantee that smooth space as we know it will emerge as the correct approximation of the theory at long distances

7. loop quantum gravity violates the rules of special relativity

8. the discrete area spectrum is not a consequence, but an assumption of loop quantum gravity

9. the discrete area spectrum is not testable

10. loop quantum gravity provides us with no tools to calculate the S-matrix

11. loop quantum gravity does not really solve any UV problems

12. loop quantum gravity is not able to calculate the black hole entropy, unlike string theory

13. loop quantum gravity has no tools to answer other important questions of quantum gravity

14. the criticisms of loop quantum gravity regarding other fields of physics are completely misguided

15.loop quantum gravity calls for "background independence" are misguided

16.loop quantum gravity is not science


The numbered points are connected to deeper explanations.

Criticisms of string theory can follow in someone else's post. With the group in favor of LQG they should be able together their heads and come up with lots of things

Current theories of gravity are based on the geometric curvature of space.

Current theories of other fundamental forces in the universe are 'quantum field theories', where particles pass other particles back and forth among themselves to interact.
We know that geometric gravity theories conflict with quantum field theories, and that this conflict means that we don't know what happens under extreme conditions.

A quantum theory of gravity would involve particles passing 'gravitons' back and forth among themselves. This quantum theory would probably be a more accurate description of gravity, and might be accurate enough to describe the extreme conditions found at the center of a black hole.

David Palmer
for Ask a High-Energy Astronomer

Quantum Gravity

Quantum gravity is the field of theoretical physics attempting to unify the subjects of Quantum mechanics and General relativity.

Much of the difficulty in merging these theories comes from the radically different assumptions that these theories have on how the universe works. Quantum mechanics depends on particle fields embedded in the flat space-time of either Newtonian mechanics or special relativity. Einstein's theory of general relativity models gravity as a curvature within space-time that changes as mass moves. The most obvious ways of combining the two (such as treating gravity as simply another particle field) run quickly into what is known as the renormalization problem. Gravity particles would attract each other and if you add together all of the interactions you end up with many infinite results which can not easily be cancelled out. This is in contrast with quantum electrodynamics where the interactions do result in some infinite results, but those are few enough in number to be removable via renormalization.

Another difficulty comes from the success of both quantum mechanics and general relativity. Both have been highly successful and there are no
known phenomenon that contradict the two. The energies and conditions at which quantum gravity are likely to be important are inaccessible to laboratory experiments. The result of this is that there are no experimental
observations which would provide any hints as to how to combine the two.

The general approach taken in deriving a theory of quantum gravity is to
assume that the underlying theory will be simple and elegant and then to
look at current theories for symmetries and hints for how to combine them
elegantly into a overarching theory. One problem with this approach is
that it is not known if quantum gravity will be a simple and elegant theory.

Such a theory is required in order to understand those problems involving the combination of very large mass or energy and very small dimensions of space, such as the behaviour of black holes, and the origin of the universe.

There are a number of proposed quantum gravity theories and proto-theories, including (for example) string theory and the loop quantum gravity of Smolin and Rovelli - see http://www.livingreviews.org/Articles/Volume1/1998-1rovelli/
The Noncommutative geometry of Alain Connes, and Twistor theory, of Roger Penrose, are also theories of quantum gravity

The Quantum Gravity Concept Map is a highly experimental work: it's goals are to help the author organize his own understanding of the subject, and to test the hypothesis that html is a natural language for the construction of a concept map.

Quantum gravity is the field of theoretical physics attempting to unify the theory of quantum mechanics, which describes three of the fundamental forces of nature, with general relativity, the theory of the fourth fundamental force: gravity. The ultimate goal is a unified framework for all fundamental forces—a theory of everything


A history of the Planck values provides interesting material for reflections on timely and premature discoveries in the history of science. Today, the Planck values are more a part of physics itself than of its history. They are mentioned in connection with the cosmology of the early universe as well as in connection with particle physics. In considering certain problems associated with a unified theory (including the question of the stability of the proton), theorists discovered a characteristic mass ~ 1016mp (mpis the proton mass). To ground such a great value, one first refers to the still greater mass 1019mp. In the words of Steven Weinberg:

This is known as the Planck mass, after Max Planck, who noted in 1900 that some such mass would appear naturally in any attempt to combine his quantum theory with the theory of gravitation. The Planck mass is roughly the energy at which the gravitational force between particles becomes stronger than the electroweak or the strong forces. In order to avoid an inconsistency between quantum mechanics and general relativity, some new features must enter physics at some energy at or below 1019 proton masses. (Weinberg 1981, p. 71).

The fact that Weinberg takes such liberties with history in this quotation is evidence of the need to describe the real historical circumstances in which the Planck mass arose. As we saw, when Planck introduced the mass (ch/G)1/2 (~ 1019mp) in 1899, he did not intend to combine the theory of gravitation with quantum theory; he did not even suppose that his new constant would result in a new physical theory. The first "attempt to combine the quantum theory with the theory of gravitation," which demonstrated that "in order to avoid an inconsistency between quantum mechanics and general relativity, some new features must enter physics," was made by Bronstein in 1935. That the Planck mass may be regarded as a quantum-gravitational scale was pointed out explicitly by Klein and Wheeler twenty years later. At the same time, Landau also noted that the Planck energy (mass) corresponds to an equality of gravitational and electromagnetic interactions.

Theoretical physicists are now confident that the role of the Planck values in quantum gravity, cosmology, and elementary particle theory will emerge from a unified theory of all fundamental interactions and that the Planck scales characterize the region in which the intensities of all fundamental interactions become comparable. If these expectations come true, the present report might become useful as the historical introduction for the book that it is currently impossible to write, The Small-Scale Structure of Space-Time.

The struggle to free ourselves from background structures began long before Einstein developed general relativity, and is still not complete. The conflict between [B]Ptolemaic and Copernican cosmologies[/B], the dispute between Newton and Leibniz concerning absolute and relative motion, and the modern arguments concerning the `problem of time' in quantum gravity -- all are but chapters in the story of this struggle. I do not have room to sketch this story here, nor even to make more precise the all-important notion of `geometrical structure'. I can only point the reader towards the literature, starting perhaps with the books by Barbour [9] and Earman [15], various papers by Rovelli [25,26,27], and the many references therein.

String theory has not gone far in this direction. This theory is usually formulated with the help of a metric on spacetime, which is treated as a background structure rather than a local degree of freedom like the rest. Most string theorists recognize that this is an unsatisfactory situation, and by now many are struggling towards a background-free formulation of the theory. However, in the words of two experts [18], ``it seems that a still more radical departure from conventional ideas about space and time may be required in order to arrive at a truly background independent formulation.