Comments on: 175. Holographic principle for dummies

By: Raphael

Raphael — Wed, 13 Jan 2010 17:43:51 +0000

What is the radius of a black hole? Is that the radius of its event horizon? Does a black hole have a radius? I thought that a black hole is pointlike object with infinite density? Emphasis on ‘pointlike’.

Interesting food for thought.

Thanks.

By: Lubos Motl

Lubos Motl — Mon, 12 Jan 2009 22:36:01 +0000

Priv?t Dmitrij,

it’s actually only one sentence later in the text – saying that the additional, radial, holographic dimension is encoded in the scale of the stereogram patterns (the periodicity in the x-direction), much like the information about the r-position in AdS is encoded in the scale in quantum gravity, too.

Best wishes
Lubos

By: Dmitry

Dmitry — Mon, 12 Jan 2009 20:51:39 +0000

Nice! Updated the post to link to yours. But you did not explain why stereograms are good as example of holographic principle

Cheers,
Dmitry.

By: Lubos Motl

Lubos Motl — Mon, 12 Jan 2009 18:13:24 +0000

Hi Dmitry, here is an TRF article with a Mathematica notebook

http://motls.blogspot.com/2009.....grams.html

By: Dmitry

Dmitry — Mon, 12 Jan 2009 14:56:15 +0000

Eventually, I will sink you in traffic, Motl

By: Lubos Motl

Lubos Motl — Mon, 12 Jan 2009 12:36:56 +0000

Incidentally, in advance, the technical “Wikipedia” name for these particular stereographs are

http://en.wikipedia.org/wiki/Autostereogram

By: Lubos Motl

Lubos Motl — Mon, 12 Jan 2009 12:34:18 +0000

Hi Dmitry, I still maintain some kind of Turbo Pascal on my desktop PC but I don’t think that it is really an up-to-date software. So it would be better to rewrite the program into something more modern, including Mathematica, despite a possible slowdown.

I can write an English version of the explanation why the “dinograms”, as I called it, work, but your indication that it would boost the traffic sounds unlikely, unless you count roughly 3.1415926 visits added as clicks from your blog!

By: Dmitry

Dmitry — Mon, 12 Jan 2009 11:51:15 +0000

Hoho, I can have some fun with your program Would you want to translate the page to English and put it on your blog? I believe, you would have some serious boost of traffic.

Cheers,
Dmitry.

By: Lubos Motl

Lubos Motl — Sun, 11 Jan 2009 21:58:16 +0000

The stereogram is a fun picture for this topic. When we were undergrads in Prague, we had so much fun with it. My friends saw it at an exhibition. I couldn’t really see it well, with my fuzzy vision, but after some time, I cracked how it worked and wrote some elementary programs that converted a function z(x,y) into this colorful picture.

http://www.kolej.mff.cuni.cz/~.....node2.html

In fact, I should recreate it now for Mathematica, even though it might be slower than a compiled program in Turbo Pascal. We’ll see. It should be fast today even if interpreted.