Sunday, March 1, 2015

Holographic principle is poorly understood

Peter Woit quotes:
Perhaps there is no greater illustration of Nature’s subtlety than what we call the holographic principle. This principle says that, in a sense, all the information that is stored in this room, or any room, is really encoded entirely and with perfect accuracy on the boundary of the room, on its walls, ceiling and floor. Things just don’t seem that way, and if we underestimate the subtlety of Nature we’ll conclude that it can’t possibly be true. But unless our current ideas about the quantum theory of gravity are on the wrong track, it really is true. It’s just that the holographic encoding of information on the boundary of the room is extremely complex and we don’t really understand in detail how to decode it. At least not yet.

This holographic principle, arguably the deepest idea about physics to emerge in my lifetime, is still mysterious. How can we make progress toward understanding it well enough to explain it to freshmen?
And then comments:
From what I can tell, the problem is not that it can’t be explained to freshmen, but that it can’t be explained precisely to anyone, since it is very poorly understood.
I left this comment:
What is so profound about saying that things may be determined by boundary data? My textbooks are filled with boundary value and initial value problems. Some are centuries old. The boundary of a black hole mixes space and time, so the distinction between the 2 kinds of problems may not be so clear. But either way, a lot of physical theories say that things are determined by data on one lower dimension.
He deleted my comment, so I am posting it here. After that, someone posted a similar comment:
On the topic of the holographic principle being held in such high regard, I have a naive question. What is the difference between the holographic principle and specifying the physics via boundary conditions? “all information in the room is in the walls” seems like an obvious quote given that the fundamental field equations are second order and hence are uniquely specified by giving the values of the fields on the boundary of the region?
I do not think that his answer is very satisfactory, but you are welcome to read it.


  1. The simple reason the 'holographic principle' can not be explained to poor hapless freshmen is because it's complete and utter bullshit.

    Anything that invokes imaginary black holes which have not been observed, or measured, and thus can not be analyzed, as the theoretical imaginary basis of 'information' on imaginary two dimensional walls of imaginary pseudo three dimensional rooms, is no where even remotely close to science, physics, or even really bad deconstructivist cubist revival. It makes me very sad that the drug induced dementia of math majors is now called 'Nature’s subtlety', or 'the deepest idea about physics to emerge in my lifetime.'

    I do believe the secrets of the universe are in no danger whatsoever of being discovered by pot heads on a bad trip.

  2. Deleted your comment? Why? does Woit regularly do that? Deleting span and comments swearing aimlessly in all caps is fine, but I loose all respect for someone who deletes arguments they don't like.

  3. Why do people read Woit at all. Waste of time. Really, these buffoons Roger is infatuated with is in can't even keep the lights on is the future. Heavy industry disappears and replaced with morons from universities doing their PT Barnum act.

  4. Woit deletes comments if he considers them off-topic.

  5. You know, I never see someone lay a map on the floor and start walking around on it trying to get somewhere. Well, until you discover mathematics where a posteriori axiomatic deduction is really fictions combined with induction by way of the law of large numbers. Sometimes, there seems to be an unwarranted "extension".