http://www.nordita.org/hawkingradiation/_img/hawkingradiation_conference_v2.pdf http://youtu.be/DkRDmJpthXg *** 
Showing posts with label AdS/CFT. Show all posts
Showing posts with label AdS/CFT. Show all posts
Tuesday, August 25, 2015
Supertranslations?
Tuesday, May 05, 2015
The Mera Lattice
There are reasons this information is meaningful to me and I hope to explain myself shortly.
See Also:
Consistency Conditions for an AdS/MERA Correspondence
Ning Bao, ChunJun Cao, Sean M. Carroll, Aidan ChatwinDavies, Nicholas HunterJones, Jason Pollack, Grant N. Remmen(Submitted on 24 Apr 2015)The Multiscale Entanglement Renormalization Ansatz (MERA) is a tensor network that provides an efficient way of variationally estimating the ground state of a critical quantum system. The network geometry resembles a discretization of spatial slices of an AdS spacetime and "geodesics" in the MERA reproduce the RyuTakayanagi formula for the entanglement entropy of a boundary region in terms of bulk properties. It has therefore been suggested that there could be an AdS/MERA correspondence, relating states in the Hilbert space of the boundary quantum system to ones defined on the bulk lattice. Here we investigate this proposal and derive necessary conditions for it to apply, using geometric features and entropy inequalities that we expect to hold in the bulk. We show that, perhaps unsurprisingly, the MERA lattice can only describe physics on length scales larger than the AdS radius. Further, using the covariant entropy bound in the bulk, we show that there are no conventional MERA parameters that completely reproduce bulk physics even on superAdS scales. We suggest modifications or generalizations of this kind of tensor network that may be able to provide a more robust correspondence. See: http://arxiv.org/abs/1504.06632
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See Also:
 Does Spacetime Emerge From Quantum Information? by Sean Carroll
 How Quantum Pairs Stitch SpaceTime  by Jennifer Ouellette at Quanta Magazine
Sunday, March 01, 2015
Visualizations are Important
Figure 1: Artist's conception of AdS/CFT. The evolution of the proton at different length scales is mapped into the compact AdS5 dimension z. Dirichlet baglike boundary condition, (z)jz=z0 = 0, is imposed at the confinement radius z = z0 = 1= QCD, thus limiting interquark separations. 
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 longstanding 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 quarkgluon plasma disappeared. See: String theory may hold answers about quarkgluon plasma
See Also:
Friday, October 04, 2013
A Deeper Search for Building Blocks of Nature
According to modern quantum theory, energy fields permeate the universe, and flurries of energy in these fields, called “particles” when they are pointlike and “waves” when they are diffuse, serve as the building blocks of matter and forces. But new findings suggest this waveparticle picture offers only a superficial view of nature’s constituents. See:
Signs of a Stranger, Deeper Side to Nature’s Building Blocks
By: Natalie Wolchover, Quanta Magazine, July 1, 2013
Friday, September 14, 2012
Computational Dilemma
Riemannian Geometry, also known as elliptical geometry, is the geometry of the surface of a sphere. It replaces Euclid's Parallel Postulate with, "Through any point in the plane, there exists no line parallel to a given line." A line in this geometry is a great circle. The sum of the angles of a triangle in Riemannian Geometry is > 180°.
Friedman Equation What is p density.
What are the three models of geometry? k=1, K=0, k+1
Negative curvature Omega=the actual density to the critical density
If we triangulate Omega, the universe in which we are in, Omega m(mass)+ Omega(a vacuum), what position geometrically, would our universe hold from the coordinates given? The basic understanding is the understanding of the evolution of Euclidean geometries toward the revelation of a dynamical understanding in the continued expression of that geometry toward a non Euclidean freedom within context of the universe..
Maybe one should look for "a location" and then proceed from there?
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 fivedimensional spacetime ("anti–de Sitter") and its fourdimensional boundary. In effect, the 5D universe is recorded like a hologram on the 4D surface at its periphery. Superstring theory rules in the 5D spacetime, but a socalled conformal field theory of point particles operates on the 4D hologram A black hole in the 5D spacetime is equivalent to hot radiation on the hologramfor 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 directlywe 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
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 onetoone 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
The problem is the further you go in terms of particle reductionism you meet a problem with discreteness in terms of "continuity of expression." I know what to call it and it is of value in science investigation. Which means the paradigmatic values with which one is govern by using discreteness in terms of lets say computational values might suffer?
While one might think that it would be easy to accept a foundational approach toward some computational view of reality that view suffers under the plight of what exists in terms of information out there?
If such a view of computational validation works in terms of viewing "a second life" then how would you approach the resolvability of mathematical functions that exist in abstractness and are applied to the nature of our expressions? Why has computations not solved the mathematical hypothesis of lets say Riemann?
Joel:I wonder if this is related to the issue of "noncomputability" of the human mind, put forward by Roger Penrose. Is this why we humans can do mathematics whereas a computer cannot ?
There are some interesting quotes here in following article that come real close to what is implied by that difference.
You raised a question that has always been a troubling one for me. On a general level how could such views have been arrived at that would allow one to access such a mathematical world?
The idea being that to get to the truth one had to turn inside and find the very roots of all thought in some geometrical form. The closer to that truth, the very understanding and schematics drawn in that form. Not all can say the search for such truth resides within? Why the need for such geometry in relativism? Riemann Hypothesis as a function of reality? Why has a computer not solved it?
My views were always general as to what we may have hoped to create in some kind of machine or mechanism. I just couldn't see this functionality in relation to the human brain as 1's and 0's.
I might say it never occurred to me the depth that it has occupied Penrose's Mind. The start of your question and the related perspectives of the authors revealed in the following discourse have raised a wide impact of views that seek to exemplify what is new to me as to what you are asking.
Yet the real world has made major advancements in terms of digital physics and hyper physics. Has any of this touched the the nature of consciousness. This would then lead to Penrose angle in relation to what consciousness is capable of and what a machine is capable of. That would be my guess.
Can one gleam the understanding of what exists all around them without the knowledge of how one can look at what is available to us in terms of our observations? You have to be able to use "distance" in order to arrive at the conclusion about the current state in terms of the geometry in order to understand how such perceptions are relevant characterization toward explaining the space and what may drive the universe in terms of it's expression.
So there are many on going experiments that help to further question that perspective test it and validate it.
The problem is that at a certain length things break down. How can consciousness then be imparted to what is geometrically inherent in our expressions of the reality in which we live? Topology? Continuity of expression?
Paul Where Do We Come From? What Are We? Where Are We Going?
"On the right (Where do we come from?), we see the baby, and three young women  those who are closest to that eternal mystery. In the center, Gauguin meditates on what we are. Here are two women, talking about destiny (or so he described them), a man looking puzzled and halfaggressive, and in the middle, a youth plucking the fruit of experience. This has nothing to do, I feel sure, with the Garden of Eden; it is humanity's innocent and natural desire to live and to search for more life. A child eats the fruit, overlooked by the remote presence of an idol  emblem of our need for the spiritual. There are women (one mysteriously curled up into a shell), and there are animals with whom we share the world: a goat, a cat, and kittens. In the final section (Where are we going?), a beautiful young woman broods, and an old woman prepares to die. Her pallor and gray hair tell us so, but the message is underscored by the presence of a strange white bird. I once described it as "a mutated puffin," and I do not think I can do better. It is Gauguin's symbol of the afterlife, of the unknown (just as the dog, on the far right, is his symbol of himself).
One then ponders how such a universe is part of something much greater in expression that one might want to see how this continuity of expression is portrayed in our universe. How such a balance is struck to maintain this feature as a geometrical understanding?
You have to go outside the box. Cosmologists are limited by this perspective. Others venture well beyond the constrains applied by them. About a beginning and an end and all that in between. Birth and death are set within the greater expression of such a universe, on and on.
See:
Tuesday, May 15, 2012
Illusions of Grandeur?
Illusions of Gravity 
Three spatial dimensions are visible all around usup/down, left/right, forward/backward. Add time to the mix, and the result is a fourdimensional blending of space and time known as spacetime. Thus, we live in a fourdimensional universe. Or do we?
Amazingly, some new theories of physics predict that one of the three dimensions of space could be a kind of an illusionthat in actuality all the particles and fields that make up reality are moving about in a twodimensional realm like the Flatland of Edwin A. Abbott. Gravity, too, would be part of the illusion: a force that is not present in the twodimensional world but that materializes along with the emergence of the illusory third dimension.
UC Berkeley's Raphael Bousso presents a friendly introduction to the ideas behind the holographic principle, which may be very important in the hunt for a theory of quantum gravity. Series: "Lawrence Berkeley National Laboratory Summer Lecture Series" [3/2006] [Science] [Show ID: 11140]
This is just a recoup of what had been transpiring since 2005. We have a pretty good picture of the ways such distinctions are held for perspective so that we may look inside the black hole? The labels of this blog entry help with this refreshing.
See Also:
Friday, October 14, 2011
Jets in a Medium
[Picture credit: Thorsten Renk, Slide 17 of this presentention] 
Centrality Dependance 
See: AdS/CFT confronts data
Friday, September 23, 2011
Plato's Cave(Animated Version)
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Hyperreality is used in semiotics and postmodern philosophy to describe a hypothetical inability of consciousness to distinguish reality from fantasy, especially in technologically advanced postmodern cultures. Hyperreality is a means to characterize the way consciousness defines what is actually "real" in a world where a multitude of media can radically shape and filter an original event or experience. Some famous theorists of hyperreality include Jean Baudrillard, Albert Borgmann, Daniel Boorstin, and Umberto Eco.
Photomontage of 16 photos which have been digitally manipulated in Photoshop to give the impression that it is a real landscape 
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The medium is the message is a phrase coined by Marshall McLuhan meaning that the form of a medium embeds itself in the message, creating a symbiotic relationship by which the medium influences how the message is perceived. See: The medium is the message (phrase)
Monday, September 05, 2011
A Holograpical Universe
Plato likened our view of the world to that of an ancient forebear watching shadows meander across a dimly lit cave wall. He imagined our perceptions to be but a faint inkling of a far richer reality that flickers beyond reach. Two millennia later, Plato’s cave may be more than a metaphor. To turn his suggestion on its head, reality—not its mere shadow—may take place on a distant boundary surface, while everything we witness in the three common spatial dimensions is a projection of that faraway unfolding. Reality, that is, may be akin to a hologram. Or, really, a holographic movie.
The journey to this peculiar possibility combines developments deep and farflung—insights from general relativity; from research on black holes; from thermodynamics, quantum mechanics, and, most recently, string theory. The thread linking these diverse areas is the nature of information in a quantum universe.
Physicists Jacob Bekenstein and Stephen Hawking established that, for a black hole, the information storage capacity is determined not by the volume of its interior but by the area of its surface. But when the math says that a black hole’s store of information is measured by its surface area, does that merely reflect a numerical accounting, or does it mean that the black hole’s surface is where the information is actually stored? It’s a deep issue and has been pursued for decades by some of the most renowned physicists. The answer depends on whether you view the black hole from the outside or from the inside—and from the outside, there’s good reason to believe that information is indeed stored at the event horizon. This doesn’t merely highlight a peculiar feature of black holes. Black holes don’t just tell us about how black holes store information. Black holes inform us about information storage in any context. See:Our Universe May Be a Giant Hologram
See Also: Physics and Philosophie Pay attention too, #8. (And Stefan submits: What is the ontological status of AdS/CFT?)[also pay attention to comments relating to #8]
Wednesday, June 15, 2011
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
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Conformal Field Theory
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?
Page 171 and 172 0f, Three Roads to Quantum Gravity by Lee Smolin
Juan Maldacena:
Pg 198, The Universe in Nutshell, by Stephen Hawking
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?
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 longstanding 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 quarkgluon plasma disappeared.See: String theory may hold answers about quarkgluon 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 fivedimensional spacetime ("anti–de Sitter") and its fourdimensional boundary. In effect, the 5D universe is recorded like a hologram on the 4D surface at its periphery. Superstring theory rules in the 5D spacetime, but a socalled conformal field theory of point particles operates on the 4D hologram. A black hole in the 5D spacetime is equivalent to hot radiation on the hologramfor 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
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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 directlywe 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 fivedimensional curved spacetime 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 spacetime. In this fivedimensional spacetime, 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 fivedimensional spacetime can even look pointlike when they are close to the boundary. Polchinski and Strassler1 show that when an energetic fourdimensional 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 pointlike object. So a stringlike interpretation of a proton is not at odds with the observation that there are pointlike 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 onetoone 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 5dimensional field equations were simply the higherdimensional 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 higherdimension 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 4dimensional 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)
Tuesday, February 16, 2010
Article From New York Times and More
HOT A computer rendition of 4trilliondegree Celsius quarkgluon plasma created in a demonstration of what scientists suspect shaped cosmic history.
In Brookhaven Collider, Scientists Briefly Break a Law of Nature
The Brookhaven scientists and their colleagues discussed their latest results from RHIC in talks and a news conference at a meeting of the American Physical Society Monday in Washington, and in a pair of papers submitted to Physical Review Letters. “This is a view of what the world was like at 2 microseconds,” said Jack Sandweiss of Yale, a member of the Brookhaven team, calling it, “a seething cauldron.”See more at above link.
Among other things, the group announced it had succeeded in measuring the temperature of the quarkgluon plasma as 4 trillion degrees Celsius, “by far the hottest matter ever made,” Dr. Vigdor said. That is 250,000 times hotter than the center of the Sun and well above the temperature at which theorists calculate that protons and neutrons should melt, but the quarkgluon plasma does not act the way theorists had predicted.
Instead of behaving like a perfect gas, in which every quark goes its own way independent of the others, the plasma seemed to act like a liquid. “It was a very big surprise,” Dr. Vigdor said, when it was discovered in 2005. Since then, however, theorists have revisited their calculations and found that the quark soup can be either a liquid or a gas, depending on the temperature, he explained. “This is not your father’s quarkgluon plasma,” said Barbara V. Jacak, of the State University at Stony Brook, speaking for the team that made the new measurements.
It is now thought that the plasma would have to be a million times more energetic to become a perfect gas. That is beyond the reach of any conceivable laboratory experiment, but the experiments colliding lead nuclei in the Large Hadron Collider outside Geneva next winter should reach energies high enough to see some evolution from a liquid to a gas.
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Violating Parity with Quarks and Gluons
by Sean Carroll of Cosmic Variance
This new result from RHIC doesn’t change that state of affairs, but shows how quarks and gluons can violate parity spontaneously if they are in the right environment — namely, a hot plasma with a magnetic field.
So, okay, no new laws of physics. Just a much better understanding of how the existing ones work! Which is most of what science does, after all.
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Quark–gluon plasma
From Wikipedia, the free encyclopedia
A QGP is formed at the collision point of two relativistically accelerated gold ions in the center of the STAR detector at the relativistic heavy ion collider at the Brookhaven national laboratory.
A quarkgluon plasma (QGP) or quark soup^{[1]} is a phase of quantum chromodynamics (QCD) which exists at extremely high temperature and/or density. This phase consists of (almost) free quarks and gluons, which are the basic building blocks of matter. Experiments at CERN's Super Proton Synchrotron (SPS) first tried to create the QGP in the 1980s and 1990s: the results led CERN to announce indirect evidence for a "new state of matter"^{[2]} in 2000. Current experiments at Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC) are continuing this effort.^{[3]} Three new experiments running on CERN's Large Hadron Collider (LHC), ALICE,^{[4]} ATLAS and CMS, will continue studying properties of QGP.
Contents

General introduction
The quarkgluon plasma contains quarks and gluons, just as normal (baryonic) matter does. The difference between these two phases of QCD is that in normal matter each quark either pairs up with an antiquark to form a meson or joins with two other quarks to form a baryon (such as the proton and the neutron). In the QGP, by contrast, these mesons and baryons lose their identities and dissolve into a fluid of quarks and gluons.^{[5]} In normal matter quarks are confined; in the QGP quarks are deconfined.Although the experimental high temperatures and densities predicted as producing a quarkgluon plasma have been realized in the laboratory, the resulting matter does not behave as a quasiideal state of free quarks and gluons, but, rather, as an almost perfect dense fluid.^{[6]} Actually the fact that the quarkgluon plasma will not yet be "free" at temperatures realized at present accelerators had been predicted already in 1984 ^{[7]} as a consequence of the remnant effects of confinement.
Why this is referred to as "plasma"
A plasma is matter in which charges are screened due to the presence of other mobile charges; for example: Coulomb's Law is modified to yield a distancedependent charge. In a QGP, the color charge of the quarks and gluons is screened. The QGP has other analogies with a normal plasma. There are also dissimilarities because the color charge is nonabelian, whereas the electric charge is abelian. Outside a finite volume of QGP the color electric field is not screened, so that volume of QGP must still be colorneutral. It will therefore, like a nucleus, have integer electric charge.
How the QGP is studied theoretically
One consequence of this difference is that the color charge is too large for perturbative computations which are the mainstay of QED. As a result, the main theoretical tools to explore the theory of the QGP is lattice gauge theory. The transition temperature (approximately 175 MeV) was first predicted by lattice gauge theory. Since then lattice gauge theory has been used to predict many other properties of this kind of matter. The AdS/CFT correspondence is a new interesting conjecture allowing insights in QGP.How it is created in the lab
The QGP can be created by heating matter up to a temperature of 2×10^{12} kelvin, which amounts to 175 MeV per particle. This can be accomplished by colliding two large nuclei at high energy (note that 175 MeV is not the energy of the colliding beam). Lead and gold nuclei have been used for such collisions at CERN SPS and BNL RHIC, respectively. The nuclei are accelerated to ultrarelativistic speeds and slammed into each other while Lorentz contracted. They largely pass through each other, but a resulting hot volume called a fireball is created after the collision. Once created, this fireball is expected to expand under its own pressure, and cool while expanding. By carefully studying this flow, experimentalists hope to put the theory to test.How the QGP fits into the general scheme of physics
QCD is one part of the modern theory of particle physics called the Standard Model. Other parts of this theory deal with electroweak interactions and neutrinos. The theory of electrodynamics has been tested and found correct to a few parts in a trillion. The theory of weak interactions has been tested and found correct to a few parts in a thousand. Perturbative aspects of QCD have been tested to a few percent. In contrast, nonperturbative aspects of QCD have barely been tested. The study of the QGP is part of this effort to consolidate the grand theory of particle physics.The study of the QGP is also a testing ground for finite temperature field theory, a branch of theoretical physics which seeks to understand particle physics under conditions of high temperature. Such studies are important to understand the early evolution of our universe: the first hundred microseconds or so. While this may seem esoteric, this is crucial to the physics goals of a new generation of observations of the universe (WMAP and its successors). It is also of relevance to Grand Unification Theories or 'GUTS' which seek to unify the four fundamental forces of nature.
Expected properties
Thermodynamics
The crossover temperature from the normal hadronic to the QGP phase is about 175 MeV, corresponding to an energy density of a little less than 1 GeV/fm^{3}. For relativistic matter, pressure and temperature are not independent variables, so the equation of state is a relation between the energy density and the pressure. This has been found through lattice computations, and compared to both perturbation theory and string theory. This is still a matter of active research. Response functions such as the specific heat and various quark number susceptibilities are currently being computed.Flow
The equation of state is an important input into the flow equations. The speed of sound is currently under investigation in lattice computations. The mean free path of quarks and gluons has been computed using perturbation theory as well as string theory. Lattice computations have been slower here, although the first computations of transport coefficients have recently been concluded. These indicate that the mean free time of quarks and gluons in the QGP may be comparable to the average interparticle spacing: hence the QGP is a liquid as far as its flow properties go. This is very much an active field of research, and these conclusions may evolve rapidly. The incorporation of dissipative phenomena into hydrodynamics is another recent development that is still in an active stage.Excitation spectrum
Does the QGP really contain (almost) free quarks and gluons? The study of thermodynamic and flow properties would indicate that this is an oversimplification. Many ideas are currently being evolved and will be put to test in the near future. It has been hypothesized recently that some mesons built from heavy quarks (such as the charm quark) do not dissolve until the temperature reaches about 350 MeV. This has led to speculation that many other kinds of bound states may exist in the plasma. Some static properties of the plasma (similar to the Debye screening length) constrain the excitation spectrum.Experimental situation
Those aspects of the QGP which are easiest to compute are not the ones which are the easiest to probe in experiments. While the balance of evidence points towards the QGP being the origin of the detailed properties of the fireball produced in the RHIC, this is the main barrier which prevents experimentalists from declaring a sighting of the QGP. For a summary see 2005 RHIC Assessment.The important classes of experimental observations are
 Single particle spectra (photons and dileptons)
 Strangeness production
 Photon and muon rates (and J/Ïˆ melting)
 Elliptic flow
 Jet quenching
 Fluctuations
 HanburyBrown and Twiss effect and BoseEinstein correlations
Formation of quark matter
In April 2005, formation of quark matter was tentatively confirmed by results obtained at Brookhaven National Laboratory's Relativistic Heavy Ion Collider (RHIC). The consensus of the four RHIC research groups was that they had created a quarkgluon liquid of very low viscosity. However, contrary to what was at that time still the widespread assumption, it is yet unknown from theoretical predictions whether the QCD "plasma", especially close to the transition temperature, should behave like a gas or liquid^{[8]}. Authors favoring the weakly interacting interpretation derive their assumptions from the lattice QCD calculation, where the entropy density of quarkgluon plasma approaches the weakly interacting limit. However, since both energy density and correlation shows significant deviation from the weakly interacting limit, it has been pointed out by many authors that there is in fact no reason to assume a QCD "plasma" close to the transition point should be weakly interacting, like electromagnetic plasma (see, e.g., ^{[9]}).See also
 Hadrons (that is mesons and baryons) and confinement
 Hadronization
 Neutron stars
 Plasma physics
 QCD matter Quantum Chromodynamics matter
 Quantum electrodynamics
 Quantum chromodynamics
 Quantum hydrodynamics
 Relativistic plasma
 Strangeness production
 Strange matter
References
 ^ Hadron production from a boiling quark soup: A thermodynamical quark model predicting particle ratios in hadronic collisions
 ^ A New State of Matter  Experiments
 ^ Relativistic Heavy Ion Collider, RHIC
 ^ Alice Experiment: Welcome to ALICE Portal
 ^ The Indian Lattice Gauge Theory Initiative
 ^ WA Zajc (2008). "The fluid nature of quarkgluon plasma". Nuclear Physics A 805: 283c294c. doi:10.1016/j.nuclphysa.2008.02.285. http://arxiv.org/PS_cache/arxiv/pdf/0802/0802.3552v1.pdf.
 ^ "How free is the quarkgluon plasma", M. PlÃ¼mer, S. Raha and R. M. Weiner, Nucl. Phys. A 418 (1984) 549c; Phys. Lett. B139 (1984) 198
 ^ Colorsinglet clustering of partons and recombination model for hadronization of quarkgluon plasma
 ^ arXiv:nuclth/0403032v1
External links
 The Relativistic Heavy Ion Collider at Brookhaven National Laboratory
 The Alice Experiment at CERN
 The Indian Lattice Gauge Theory Initiative
 Quark matter reviews: 2004 theory, 2004 experiment
 Lattice reviews: 2003, 2005
 BBC article mentioning Brookhaven results
 Physics News Update article on the quarkgluon liquid, with links to preprints
 Read for free : "Hadrons and QuarkGluon Plasma" by Jean Letessier and Johann Rafelski Cambridge University Pres (2002) ISBN 0 521 38536 9 , Cambridge, UK;
Saturday, September 19, 2009
Macroscopic Similarities in a Microscopic World
Berkeley Lab Technology Dramatically Speeds Up Searches of Large DatabasesJon Bashor
It's not just about "mathematical abstraction" but of seeing what good it can be used for. One can be in denial about the prospects but while it gives perspective to current situations, in that it helps to direct thinking forward instead feeling as if "you are just floating in space without being able to move."
Helpless are we? Not considering flapping one's wings?
Imagine indeed then, trying to orientate direction toward the spacecraft when "floating in space" seems like having to attempt to ride a bicycle for the first time, so one should know we must balance ourselves while doing the appropriate movements directed to where we want to go. It's something that has to be learn in theoretical enterprise while still held to earth's environ?
So how has this helped the idea of "minimum length?"
***
Looking back in time toward the beginning of our universe has been one of the things that have been occupying my time as I look through experimental procedures that have been developed. While LHC provides a template of all the historical drama of science put forward, it is also a platform in my mind for pushing forward perspective from "a beginning of time scenario" that helps us identify what happens in that formation. Helps us to orientate space and what happens to it.
It provides for me a place where we can talk about a large scale situation in terms of the universe as to what it contains to help motivate this universe to become what it is.
Cycle of Birth, Life, and DeathOrigin, Indentity, and Destiny by Gabriele Veneziano
So how did this process help orientate the things that were brought forward under the idea that the universe is a "cosmological box" that people want to talk about, while in my mind ,it became much more flexible topic when Venezianno began to talk about what came before. What existed outside that box. Abstractly, the box had six faces, to which direction of possibilities became part of the depth of this situation. It was a matter indeed of thinking outside the box.
I know that for some, why waste one's time, but for me it is the motivator( not God as a creator, but of what actually propels this universe) and to what can exist now that draws my attention. It has been ever so slightly pushed "back in time" to see that the universe began with "microscopic processes that defines the state of the state of the universe in the way it is now." The LHC should be able to answer this although it is still restricted by the energy valuation given to this process.
Physical Reality Of String Theory Shown In Quantumcritical State Of Electrons
In the world of physics, one of the most elusive events is the creation and detection of “quarkgluon plasma,” the theorized atomic outcome of the “Big Bang” which could provide insight into the origins of the universe. By using experiments that involve millions of particle collisions, researchers hope to find unambiguous evidence of quarkgluon plasma.
It's not just about "mathematical abstraction" but of seeing what good it can be used for. One can be in denial about the prospects but while it gives perspective to current situations, in that it helps to direct thinking forward instead feeling as if "you are just floating in space without being able to move."
Helpless are we? Not considering flapping one's wings?
Imagine indeed then, trying to orientate direction toward the spacecraft when "floating in space" seems like having to attempt to ride a bicycle for the first time, so one should know we must balance ourselves while doing the appropriate movements directed to where we want to go. It's something that has to be learn in theoretical enterprise while still held to earth's environ?
There might be a middle way. String theory's mathematical tools were designed to unlock the most profound secrets of the cosmos, but they could have a far less esoteric purpose: to tease out the properties of some of the most complex yet useful types of material here on Earth.
Both string theorists and condensed matter physicists  those studying the properties of complex matter phases such as solids and liquids  are enthused by the development. "I am flabbergasted," says Jan Zaanen, a condensed matter theorist from the University of Leiden in the Netherlands. "The theory is calculating precisely what we are seeing in experiments." See:What string theory is really good for
So how has this helped the idea of "minimum length?"
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 LiquidSo we have a beginning here for consideration within the frame work of Condense matter theorist state of existence? String theory is working along side of to direct the idea of matter formation?
Our work is about comparing the data we collect in the STAR detector with modern calculations, so that we can write down equations on paper that exactly describe how the quarkgluon plasma behaves," says Jerome Lauret from Brookhaven National Laboratory. "One of the most important assumptions we've made is that, for very intense collisions, the quarkgluon plasma behaves according to hydrodynamic calculations in which the matter is like a liquid that flows with no viscosity whatsoever."
Proving that under certain conditions the quarkgluon plasma behaves according to such calculations is an exciting discovery for physicists, as it brings them a little closer to understanding how matter behaves at very small scales. But the challenge remains to determine the properties of the plasma under other conditions.
"We want to measure when the quarkgluon plasma behaves like a perfect fluid with zero viscosity, and when it doesn't," says Lauret. "When it doesn't match our calculations, what parameters do we have to change? If we can put everything together, we might have a model that reproduces everything we see in our detector." See:Probing the Perfect Liquid with the STAR Grid
***
Looking back in time toward the beginning of our universe has been one of the things that have been occupying my time as I look through experimental procedures that have been developed. While LHC provides a template of all the historical drama of science put forward, it is also a platform in my mind for pushing forward perspective from "a beginning of time scenario" that helps us identify what happens in that formation. Helps us to orientate space and what happens to it.
It provides for me a place where we can talk about a large scale situation in terms of the universe as to what it contains to help motivate this universe to become what it is.
Cycle of Birth, Life, and DeathOrigin, Indentity, and Destiny by Gabriele Veneziano
In one form or another, the issue of the ultimate beginning has engaged philosophers and theologians in nearly every culture. It is entwined with a grand set of concerns, one famously encapsulated in an 1897 painting by Paul Gauguin: D'ou venonsnous? Que sommesnous? Ou allonsnous? "Where do we come from? What are we? Where are we going?"See here for more information.
So how did this process help orientate the things that were brought forward under the idea that the universe is a "cosmological box" that people want to talk about, while in my mind ,it became much more flexible topic when Venezianno began to talk about what came before. What existed outside that box. Abstractly, the box had six faces, to which direction of possibilities became part of the depth of this situation. It was a matter indeed of thinking outside the box.
I know that for some, why waste one's time, but for me it is the motivator( not God as a creator, but of what actually propels this universe) and to what can exist now that draws my attention. It has been ever so slightly pushed "back in time" to see that the universe began with "microscopic processes that defines the state of the state of the universe in the way it is now." The LHC should be able to answer this although it is still restricted by the energy valuation given to this process.
A magnet levitating above a hightemperature superconductor, cooled with liquid nitrogen. Theoretical physicists have now used string theory to describe the quantumcritical state of electrons that can lead to hightemperature superconductivity. (Credit: MaiLinh Doan / Courtesy of Wikimedia Commons) See:
Physical Reality Of String Theory Shown In Quantumcritical State Of Electrons
Quantum soupSee Also:
But now, Zaanen, together with his colleagues Cubrovic and Schalm, are trying to change this situation, by applying string theory to a phenomenon that physicists, including Zaanen, have for the past fifteen years been unable to explain: the quantumcritical state of electrons. This special state occurs in a material just before it becomes superconductive at high temperature. Zaanen describes the quantumcritical state as a 'quantum soup', whereby the electrons form a collective independent of distances, where the electrons exhibit the same behaviour at small quantum mechanical scale or at macroscopic human scale.
Fermions and the AdS/CFT correspondence: quantum phase transitions and the emergent Fermiliquid
A central mystery in quantum condensed matter physics is the zero temperature quantum phase transition between strongly renormalized Fermiliquids as found in heavy fermion intermetallics and possibly high Tc superconductors. Field theoretical statistical techniques are useless because of the fermion sign problem, but we will present here results showing that the mathematics of string theory is capable of describing fermionic quantum critical states. Using the AntideSitter/Conformal Field Theory (AdS/CFT) correspondence to relate fermionic quantum critical fields to a gravitational problem, we compute the spectral functions of fermions in the field theory. Deforming away from the relativistic quantum critical point by increasing the fermion density we show that a state emerges with all the features of the Fermiliquid. Tuning the scaling dimensions of the critical fermion fields we find that the quasiparticle disappears at a quantum phase transition of a purely statistical nature, not involving any symmetry change. These results are obtained by computing the solutions of a classical Dirac equation in an AdS space time containing a ReissnerNordstrom black hole, where the information regarding FermiDirac statistics in the field theory is processed by quasinormal Dirac modes at the outer horizon.
Sunday, January 25, 2009
Voxels
A generalization of a voxel is the doxel, or dynamic voxel. This is used in the case of a 4D dataset, for example, an image sequence that represents 3D space together with another dimension such as time. In this way, an image could contain 100×100×100×100 doxels, which could be seen as a series of 100 frames of a 100×100×100 volume image. Although storage and manipulation of such data uses a lot of computer memory, this allows the study of spacetime systems.
There is a discussion over at Backreaction called, Conservative solutions to the black hole information problem It deals with a paper her and Lee Smolin wrote together.
By Sabine Hossenfelder and Lee Smolin
arXiv: 0901.3156,
Submitted on 20 Jan 2009) Abstract: We review the different options for resolution of the black hole loss of information problem. We classify them first into radical options, which require a quantum theory of gravity which has large deviations from semiclassical physics on macroscopic scales, such as nonlocality or endowing horizons with special properties not seen in the semiclassical approximation, and conservative options, which do not need such help. Among the conservative options, we argue that restoring unitary evolution relies on elimination of singularities. We argue that this should hold also in the AdS/CFT correspondence.
It is important that one is set up in terms of progressing to the determination and explanation of the voxel in the context that Holography. Susskind uses it in the way one can interpret "the bit" of information.
A picture, a photograph, or a painting is not the real world that it depicts. It's flat, not full with three dimensional depth like the real thing. Look at it from the sidealmost edge on. It doesn't look anything like the real scene view from a angle. In short it's two dimensional while the world is three dimensional. The artist, using perceptual sleight of hand, has conned you into producing a three dimensional image in your brain, but in fact the information just isn't there to form a three dimensional model of the scene. There is no way to tell if that figure is a distant giant or a close midget There is no way to tell if the figure is made of plaster or if it's filled with blood or guts. The brain is providing information that is not really present in the painted strokes on the canvas or the darken grains of silver on the photographic surface. The Cosmic Landscape by Leonard Susskind, page 337 and 338
Monday, February 13, 2006
Intersection of D Branes
I'm not going to try and kid you with "this stuff," as it is extremely beyond anything that any of us mere mortal can understand. So, if such a thought would be to simplify, then how would such thinking be attributed to such model building and make it easier for us lay people to comprehend where these people are working in terms of the way they do things.
What is important is that we can derive some method to this madness:) okay! rather this abstract thinking, to show some kind of similarity in lay people's current thought patterns for easy recognition.
I'll burn in hell, if I get this wrong, but surely from my "faulty trails (not Tower)" I can be forgiven, until a clearer picture is given to us, that I could revamp all that I said, and leave for you now, the trials and tibulation of a rogue what?:)
Now you have to think about what I am saying, if you understand indeed, that such a place exists in the picture below, which for us mortals to consider. Think for a minute about the blackhole and where I had been talking in relation to the collider, as well as, the cosmic collisions taking place, with higher energy particles in our own atmosphere.
Weak field manifestation has particle consideration evident, and we find these here on earth, as neutrinos. Do You see now?
I thought this to be part of the trivial effort with which I had departed to the bulk perspective, without really undertanding how I had got there. Yet I do see in these ways and many things are encompassed within it(gravitonic concentration). I would say, like Clifford telling us about the proper way in which we should move within these mathematical environs, then I would say what a rogue scholar I make, becuase this seems be the bastard child I am whose school is by insight developement, and some of it, wrong of course. But I try.
Superstrings, black holes and gauge theories
PROSPECTS FROM STRINGS AND BRANESA.SEVRIN
The link below contains over 222 pages, so if you are on Dialup, you have to think twice about clicking on it. Another of Cosmic Variance's very own.
DBrane PrimerClifford V. Johnson
What is important is that we can derive some method to this madness:) okay! rather this abstract thinking, to show some kind of similarity in lay people's current thought patterns for easy recognition.
I'll burn in hell, if I get this wrong, but surely from my "faulty trails (not Tower)" I can be forgiven, until a clearer picture is given to us, that I could revamp all that I said, and leave for you now, the trials and tibulation of a rogue what?:)
Now you have to think about what I am saying, if you understand indeed, that such a place exists in the picture below, which for us mortals to consider. Think for a minute about the blackhole and where I had been talking in relation to the collider, as well as, the cosmic collisions taking place, with higher energy particles in our own atmosphere.
Weak field manifestation has particle consideration evident, and we find these here on earth, as neutrinos. Do You see now?
Physicists Andrew Strominger and Cumrin Vafa, showed that this exact entropy formula can be derived microscopically (including the factor of 1/4) by counting the degeneracy of quantum states of configurations of strings and Dbranes which correspond to black holes in string theory. This is compelling evidence that Dbranes can provide a short distance weak coupling description of certain black holes! For example, the class of black holes studied by Strominger and Vafa are described by 5branes, 1branes and open strings traveling down the 1brane all wrapped on a 5dimensional torus, which gives an effective one dimensional object  a black hole.
I thought this to be part of the trivial effort with which I had departed to the bulk perspective, without really undertanding how I had got there. Yet I do see in these ways and many things are encompassed within it(gravitonic concentration). I would say, like Clifford telling us about the proper way in which we should move within these mathematical environs, then I would say what a rogue scholar I make, becuase this seems be the bastard child I am whose school is by insight developement, and some of it, wrong of course. But I try.
Superstrings, black holes and gauge theories
Dbranes are nonperturbative excitations of string theory on which open strings can end. Open strings have gauge fields, so the Dbranes define a gauge theory. There is a class of black hole made of Dbranes, and these have a quantum gauge theory description. The closed strings define a field theory of gravity.
PROSPECTS FROM STRINGS AND BRANESA.SEVRIN
Strings occur in two versions: closed and open strings. Roughly speaking, one has that closed strings carry the gravitational interaction and the open strings carry the gauge interactions. While closed strings can freely propagate in space, the modern point of view is that the end points of open strings are “stuck” on pdimensional hypersurfaces, where p ∈ {1, 2, · · · , 9}. These hypersurfaces are known as Dpbranes. They are dynamical but they are extremely heavy in the perturbative regime of string theory (their tension or energy per unit of volume is inversely proportional to the string coupling constant): they are solitons. A D0brane is a pointlike object, a D1brane a stringlike object, a D2brane a membrane, ... Just as a propagating point particle sweeps out a curve – the worldline – in spacetime, a Dpbrane sweeps out a p + 1dimensional volume – the worldvolume – in the 10dimensional spacetime. The effective dynamics on the worldvolume is then described by a p + 1dimensional field theory.
Dbranes represent a key theoretical tool in the understanding of strongly coupled superstring theory and Mtheory. They have led to many striking discoveries, including the precise microphysics underlying the thermodynamic behaviour of certain black holes, and remarkable holographic dualities between largeN gauge theories and gravity. This book provides a selfcontained introduction to the technology of Dbranes, presenting the recent developments and ideas in a pedagogical manner. It is suitable for use as a textbook in graduate courses on modern string theory and theoretical particle physics, and will also be an indispensable reference for seasoned practitioners. The introductory material is developed by first starting with the main features of string theory needed to get rapidly to grips with Dbranes, uncovering further aspects while actually working with Dbranes. Many advanced applications are covered, with discussions of open problems which could form the basis for new avenues of research
The link below contains over 222 pages, so if you are on Dialup, you have to think twice about clicking on it. Another of Cosmic Variance's very own.
DBrane PrimerClifford V. Johnson
Following is a collection of lecture notes on Dbranes, which may be used by the reader as preparation for applications to modern research applications such as: the AdS/CFT and other gauge theory/geometry correspondences, Matrix Theory and stringy noncommutative geometry, etc. In attempting to be reasonably selfcontained, the notes start from classical pointparticles and develop the subject logically (but selectively) through classical strings, quantisation, Dbranes, supergravity, superstrings, string duality, including many detailed applications. Selected focus topics feature Dbranes as probes of both spacetime and gauge geometry, highlighting the role of worldvolume curvature and gauge couplings, with some nonAbelian cases. Other advanced topics which are discussed are the (presently) novel tools of research such as fractional branes, the enhancon mechanism, D(ielectric)branes and the emergence of the fuzzy/noncommutative sphere.
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