Trevor's Reviews > Decoding the Universe: How the New Science of Information Is Explaining Everything in the Cosmos, from Our Brains to Black Holes

Decoding the Universe by Charles Seife
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Jan 22, 09

bookshelves: science

I spotted this book in Readings, on the famous bargains table, and since I’d been trying to explain to a friend of mine the importance of information theory (and had made a complete dog’s breakfast of it) it became urgent that I read a book on this subject again to refresh my memory. My first taste of information theory was Grammatical Man by Jeremy Campbell – and what a joy that book was, pure magic. The only problem was that I read it probably 20 years ago and so my memory was hazy at best. And then here was a book, a book written recently, on the same topic and it looked like it would do the trick and even bring me up to date on the latest developments.

Unfortunately, I’ve struggled through this book and am a bit disappointed with it. I mean, it should be the book of the century, how did WW2 code breakers help invent a new science that may one day resolve the paradoxes between Relativity and Quantum Mechanics? How could you fail to make that an interesting story?

Look, I know, when I say that this book is hard to read you are going to say, “Well, McCandless, if you are going to persist in reading books about entropy, relativity and quantum theory it probably is a little churlish to complain about difficulty”.

Well, actually, no. The fact these topics are innately difficult is no excuse. Books ought to be clear – even about quantum theory, and that is not too much to ask or expect. And he tries to be clear, he really does try. My problem with this book throughout was that he seemed to have trouble spotting the story or with keeping to the narrative. Far too often I was left a bit lost – even though I’m rather familiar with the subject matter.

I’m going to tell you about the things you should be on the look out for in science over the next few years – maybe decades.

The first is the Higgs Boson. This is the particle that is speculated to give matter its mass. This is, at least in part, the reason the Europeans have built a great big atom smasher – in the hope of finding the Higgs Boson. One of the things that finding this particle might just do (besides confirming the Standard Model of the Atom) is perhaps show some way to unifying our field theories. And that is the second thing that you might want to keep an eye out for. You see, we have two remarkably odd, but remarkably interesting theories about how the world works – Relativity for big and fast things and Quantum Theory for small and often cold things. The only problem is that although these two theories work remarkably well on their own turf, they don’t work at all well together. In fact, they sometimes say contradictory things. If someone comes up with a way to resolve those contradictions you might well want to know about it – it will be one of our greatest intellectual achievements. And in all probability it will be said by someone talking about information theory.

One of the other things you might want to know about is the EPR or the Einstein-Podolsky-Rosen thought experiment. This is one of those things that are designed to drive you nuts about Quantum Theory, and something that justifies Bohr saying things like, “If you think you understand Quantum Mechanics you probably don’t”. But let’s take a short detour.

The big experiment in Quantum Mechanics is Young’s double-slit experiment. This is where you have a barrier that has two slits in it and a light source behind it. The light source shines on the barrier and the two slits allow light to pass through and strike a further wall. When the light from one of the slits interacts with the light from the other it will, depending on how far it has had to travel, form a series of patterns on the wall the light is shining onto. The waves will have either cancelled each other out or added together to make a series of light and dark bands. This is called an interference pattern and it was used by physicists for years to prove the wave nature of light. If light was particles you would expect to see two bright spots on the wall, not a series of light and dark patches.

Then Einstein proved that light was also a particle. And then scientists were able to send particles of light toward the Young double-slit experiment one at a time and that was when the terribly odd things that Quantum Mechanics is renowned for started to happen in all earnestness. You see, you should only get an interference pattern if there is a wave coming out of both slits, but if you are sending one particle of light at a time through the slits you shouldn’t get an interference pattern, as the single particle doesn’t have anything to interfer with (and I’m sure we all remember we should never interfer with ourselves). But the terribly strange thing is that even if you do send the light at the slits one photon at a time they still build up a pattern on the wall as if they were waves – waves going through both slits, rather than particles going through one slit at a time. Physicists explain this by saying that the particle has an undefined position as it moves towards the screen and so actually does go through both slits at once.

This is a little bit troubling, but don’t worry, it gets much worse. So, why don’t we try to trick this little particle? Why not put a detector on one of the slits and see which one the particle is actually going through. Well, as soon as you do that the experiment doesn’t work any more. Rather than getting an interference pattern you get two large bumps on the screen showing that the light particles have gone through the slits like particles and not like waves. If you don’t check they go through the slits like waves. Checking what light is up to makes a difference to how light behaves. If you are not troubled by that, I haven’t explained it as well as I should. Why should light behave differently depending on whether we are watching or not?

Quantum Mechanics is probably the most important scientific discovery of the last century. Without it there would be no TV, no computers, no fMRI, in fact, the list is almost endless. It is also deeply troubling in the sense that it plays around with our ideas of how the world ought to work. My favourite example of the importance of Quantum Mechanics over Classical Mechanics is that if it wasn’t for Quantum weirdness the sun wouldn’t shine, as the sun isn’t really big enough for the hydrogen particles to overcome their natural repulsive forces to enable fusion to occur without a bit of Quantum cheating. We owe much to Quantum Mechanics.

Einstein helped create Quantum Mechanics, but hated it. When he said that God doesn’t play dice with the universe he was talking about Quantum Mechanics, as it relies on probability theory, and Einstein didn’t like that. He also didn’t like that it contradicted things he put forward in his Theory of Relativity. In fact, he came up with the EPR thought experiment to try to prove Quantum Mechanics was internally inconsistent and that there needed to be a deeper reality that Quantum Mechanics was only hinting at. This is based on the strange fact that when two particles are formed in superposition they remain ‘entangled’ (one is always opposite to the other once we check, except they are both the opposite characteristics until we check - just like the light particle before was a wave until we checked and then it became a particle). When we finally check their properties they snap out of being both to being only one of the opposite characteristics. The other particle also snaps out of being both properties to being the opposite of the particle we checked. Quantum Theory says that even the particles themselves cannot know what their own properties are prior to us checking and yet as soon as we check one particle’s properties the other must instantaniously become the opposite. But the two particles could be half a universe apart by this stage, so the information about what one of them is would need to have travelled to its twin particle at more than the speed of light. Which, frankly, ought to be impossible.

Einstein thought this experiment would by the clincher and would show Quantum Mechanics to be fundamentally wrong, but all it showed was (when the experiment could finally be preformed) that quantum reality is deeply strange – it has been confirmed that the information between the two particles does in fact travel faster than light. Einstein’s worst nightmare. This cannot be the end of the story, and we need a deeper understanding of how the universe works to make sense of this paradox of information travelling faster than light.

This book provides an introduction into how the paradoxes between relativity and quantum mechanics might be resolved – but it does so in a way that is anything but clear. The author seeks to be clear, but misses by not keeping his readers by the hand. His editor ought to have pulled all the stuff that was tangental to the story. And should have made more readible the important bits, particularly his section on quantum computers, which proved to be almost completely unreadable even though I was keenly interested to learn more.

If I find a better book on this stuff I’ll let you know.
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Comments (showing 1-9 of 9) (9 new)

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message 1: by Meen (new)

Meen Will this one debunk string theory?


message 2: by Félix (new)

Félix What do you have against string theory?


Trevor This one is about information theory - I was trying to explain it to a friend recently, trying to explain the relationship between entropy and information, and I sounded like someone who really didn't know what he was talking about. So, reading this became a little urgent. So far, so good.

E molto facile - which is all for the best.


message 4: by Meen (new)

Meen Larry, it's just too string-y. Ewww.

You know what I really loathe? Game theory.


message 5: by Félix (new)

Félix Too game-y?


message 6: by Meen (new)

Meen Yay, Trevor! You've done more to explain quantum physics to me than I ever got from my Physics professor or Discovery channel!

:)


Trevor It is the story, they never tell the story, Mindy. I can never understand why they insist on avoiding the story.



message 8: by Ludo (new)

Ludo hello Trevor,
I liked Brian Greene's "The Fabric of the Cosmos (Space, time, and the texture of reality)" a nice introduction to String Theory, but also about classic physics and the struggle for unification between paradoxes as relativity and quantum mechanics.

Lisa Randall is still on the "to read" shelf but I was impressed by her presentation when she talked (in Antwerp, Belgium) about her research for Higgs Boson in the LHC in CERN.

Kind regards
Ludo





Trevor Hi Ludo,

I started reading Greene a month or so ago and it was utterly fascinating. I intend to go back to it. I have been worrying over that bucket of water ever since. He seemed much better at being able to tell stories.

Thanks for you comments


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