Showing posts with label Firewall. Show all posts
Showing posts with label Firewall. Show all posts

Wednesday, June 25, 2014

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

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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Black holes, quantum information, and the foundations of physics

Volume 66, Issue 4, April 2013

Quantum mechanics teaches that black holes evaporate by radiating particles—a lesson indicating that at least one pillar of modern physics must fall. See: Black holes, quantum information, and the foundations of physics by Steven B. Giddings, in Physics Today, April 2013

Based on an image from NASA/CXC/M.Weiss
Citation: Phys. Today 66, 4, 30 (2013);
image of Untitled

of the Schwarzschild black hole solution can be depicted in different ways. In this representation, ingoing light rays always travel along ingoing lines heading toward the top and left at 45°; outgoing light rays asymptotically approach 45° lines at large radius . Massive particles, with their slower speeds, must travel within the light cones (blue) between outgoing and ingoing light rays, as illustrated by the red path. No light ray can escape to infinity from inside the vertical dotted line, the horizon located at the mass-dependent Schwarzschild radius (). Instead, any trajectory beginning inside the horizon is pulled to a central point, the singularity at = 0, where spacetime curvature becomes infinite.
Citation: Phys. Today 66, 4, 30 (2013);

Thursday, January 30, 2014

Gravitational Collapse and the Horizon

It has been suggested [1] that the resolution of the information paradox for evaporating black holes is that the holes are surrounded by firewalls, bolts of outgoing radiation that would destroy any infalling observer. Such firewalls would break the CPT invariance of quantum gravity and seem to be ruled out on other grounds. A different resolution of the paradox is proposed, namely that gravitational collapse produces apparent horizons but no event horizons behind which information is lost. This proposal is supported by ADS-CFT and is the only resolution of the paradox compatible with CPT. The collapse to form a black hole will in general be chaotic and the dual CFT on the boundary of ADS will be turbulent. Thus, like weather forecasting on Earth, information will effectively be lost, although there would be no loss of unitarity. See: Information Preservation and Weather Forecasting for Black Holes


r 0 = G M c 2
The critical radius r 0 where the energy of m changes sign is called the horizon radius. The region inside this critical radius is called a black hole. See: Can we make objects of zero mass?
Implications for the black hole problem:Recall that vacuum fluctuations near the horizon had lead to the creation of particle pairs See: The Black Hole Information Paradox

Ahmed Almheiri, Donald Marolf, Joseph Polchinski, James Sully
We argue that the following three statements cannot all be true: (i) Hawking radiation is in a pure state, (ii) the information carried by the radiation is emitted from the region near the horizon, with low energy effective field theory valid beyond some microscopic distance from the horizon, and (iii) the infalling observer encounters nothing unusual at the horizon. Perhaps the most conservative resolution is that the infalling observer burns up at the horizon. Alternatives would seem to require novel dynamics that nevertheless cause notable violations of semiclassical physics at macroscopic distances from the horizon. Black Hole: Complementarity vs Firewall

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Tuesday, December 24, 2013

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

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

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Wednesday, October 23, 2013

Analogies Make You Think

Falling into a Blackhole- On Sept. 25, four theoretical physicists — Raphael Bousso (U.C. Berkeley), Juan Maldacena (Institute for Advanced Study), Joseph Polchinski (U.C. Santa Barbara) and Leonard Susskind (Stanford University) — answered your questions about the latest theories about what happens when matter falls into a black hole and how these ideas are prompting researchers to reconsider our understanding of gravity.

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Wednesday, July 10, 2013

The black-hole information paradox, complementarity, and firewalls by Leonard Susskind

The black-hole information paradox, complementarity, and firewalls by Leonard Susskind,

Stanford University, at the University of California, Santa Cruz Institute for the Philosophy of Cosmology July 5, 2013

Saturday, June 15, 2013

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

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Sunday, September 23, 2012

Black Hole Thoughts are Spoken: Complementarity vs Firewall

Black Holes: Complementarity vs Firewalls

  • Subtitle: Strings 2012
  • Speaker: Raphael Bousso
  • Location: Ludwig-Maximilians-Universität München
  • Date: 27.07.2012 @ 16:04

Ahmed Almheiri, Donald Marolf, Joseph Polchinski, James Sully

We argue that the following three statements cannot all be true: (i) Hawking radiation is in a pure state, (ii) the information carried by the radiation is emitted from the region near the horizon, with low energy effective field theory valid beyond some microscopic distance from the horizon, and (iii) the infalling observer encounters nothing unusual at the horizon. Perhaps the most conservative resolution is that the infalling observer burns up at the horizon. Alternatives would seem to require novel dynamics that nevertheless cause notable violations of semiclassical physics at macroscopic distances from the horizon. Black Hole: Complementarity vs Firewall

This lecture presents some particular thoughts that rang a bell for me in terms of what reporting was done here earlier on the thought experiments by Susskind on how one may interpret information gained by the process of entanglement to an observer outside the black hole.

See:The elephant and the event horizon 26 October 2006 by Amanda Gefter at New Scientist.

 Also See: Where Susskind leaves off, Seth Lloyd begins

Various neutron interferometry experiments demonstrate the subtlety of the notions of duality and complementarity. By passing through the interferometer, the neutron appears to act as a wave. Yet upon passage, the neutron is subject to gravitation. As the neutron interferometer is rotated through Earth's gravitational field a phase change between the two arms of the interferometer can be observed, accompanied by a change in the constructive and destructive interference of the neutron waves on exit from the interferometer. Some interpretations claim that understanding the interference effect requires one to concede that a single neutron takes both paths through the interferometer at the same time; a single neutron would "be in two places at once", as it were. Since the two paths through a neutron interferometer can be as far as 5 cm to 15 cm apart, the effect is hardly microscopic. This is similar to traditional double-slit and mirror interferometer experiments where the slits (or mirrors) can be arbitrarily far apart. So, in interference and diffraction experiments, neutrons behave the same way as photons (or electrons) of corresponding wavelength. See: Complementarity (physics)

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Monday, June 11, 2012

The Black Hole of What?

In networking, black holes refer to places in the network where incoming traffic is silently discarded (or "dropped"), without informing the source that the data did not reach its intended recipient.

When examining the topology of the network, the black holes themselves are invisible, and can only be detected by monitoring the lost traffic; hence the name.


Dead addresses

The most common form of black hole is simply an IP address that specifies a host machine that is not running or an address to which no host has been assigned.
Even though TCP/IP provides means of communicating the delivery failure back to the sender via ICMP, traffic destined for such addresses is often just dropped.
Note that a dead address will be undetectable only to protocols that are both connectionless and unreliable (e.g., UDP). Connection-oriented or reliable protocols (TCP, RUDP) will either fail to connect to a dead address or will fail to receive expected acknowledgements.

Firewalls and "stealth" ports

Most firewalls can be configured to silently discard packets addressed to forbidden hosts or ports, resulting in small or large "black holes" in the network.

Black hole filtering

Black hole filtering refers specifically to dropping packets at the routing level, usually using a routing protocol to implement the filtering on several routers at once, often dynamically to respond quickly to distributed denial-of-service attacks.

PMTUD black holes

Some firewalls incorrectly discard all ICMP packets, including the ones needed for Path MTU discovery to work correctly. This causes TCP connections from/to/through hosts with a lower MTU to hang.

Black hole e-mail addresses

A black hole e-mail address is an e-mail address which is valid (messages sent to it will not generate errors), but to which all messages sent are automatically deleted, and never stored or seen by humans. These addresses are often used as return addresses for automated e-mails.

See also

External links

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

Spacetime in String Theory
Dr. Gary Horowitz, UCSB

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
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


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.


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


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)