Quantum Physics...

[RedCommieBear]

I've recently been trying to learn about quantum physics. The problem is, I have yet to find a simple explanation of it. The wikipedia artcle is no help and is written way past my knowledge. So, I'd really appreciate it if some would give me a simple explanation of quantum physics?

Thanks for the links and explanations.

[bezdomni]

Quantum Physics isn't really something you can understand in its entirety without a lot of work.

There are some other threads on this topic though that will explain it fairly well.

Science Links Thread (http://www.revleft.com/index.php?showtopic=40779)

Quantum Physics Thread (http://www.revleft.com/index.php?showtopic=60768)

[ComradeRed]

Quantum mechanics:

State space -> Hilbert space
observables as real valued functions of state space -> operators of basis vectors of the system represented by the Hilbert space.

It doesn't get any simpler than that.

[redcannon]

just remember what Neils Bohr said:

"Anyone who says they understand Quantum Physics the first time it is explained to them didn't understand a word."

[( R )evolution]

ComradeRed you are a fucking genius with this math shit god dam.

[ComradeRed]

Originally posted by [email protected] 27, 2007 06:36 pm
just remember what Neils Bohr said:

"Anyone who says they understand Quantum Physics the first time it is explained to them didn't understand a word."
...and Bohr was just as wrong with his model of the atom too.


ComradeRed you are a fucking genius with this math shit god dam. No, it took me a while to get it. Uh, if you know thermodynamics (like if you know what the Boltzmann sum is), then you ought to learn the sum over histories version of quantum mechanics (which is best explained in Anthony Zee's Quantum Field Theory in a Nutshell).

Unless you know Hamiltonian/Lagrangian mechanics cold, you won't have a chance in hell of understanding quantum mechanics.

You also need to know linear algebra, operator theory, hilbert spaces, that is if you want to learn canonical quantum mechanics.

For the sum over histories you only need calculus and to be friendly to the concept of complex variables.

But if you are trying to understand it conceptually look at Feynman's third volume from his set of lectures on quantum mechanics, a rather eloquent explanation of it. There really is no way to seperate quantum mechanical concepts from the math of it though.

[bloody_capitalist_sham]

CR is this the same as quantum mechanics?

And is that compatible with Marxism, because i watched a documentary about it, and the experts said some stuff that didn't sound to materialist....

[RebelDog]

Originally posted by Red [email protected] 28, 2007 12:06 am
I've recently been trying to learn about quantum physics. The problem is, I have yet to find a simple explanation of it. The wikipedia artcle is no help and is written way past my knowledge. So, I'd really appreciate it if some would give me a simple explanation of quantum physics?

Thanks for the links and explanations.
Try this short video of the famous double slit experiment. Maybe you've already seen it.

http://video.google.co.uk/videoplay?docid=...8&q=double+slit (http://video.google.co.uk/videoplay?docid=-4237751840526284618&q=double+slit)

I believe that molecules have now also been found to have an interferance pattern, remarkable.

[ComradeRed]

Originally posted by [email protected] 28, 2007 05:22 am
CR is this the same as quantum mechanics?
Which quantum physics or quantum field theory? The former yes, the latter is essentially the same in principle but is applied to fields (it's also applicable to mechanics if you do it right; so yes).


And is that compatible with Marxism, because i watched a documentary about it, and the experts said some stuff that didn't sound to materialist.... There are various "interpretations" (i.e. schools of thought) of quantum mechanics that have different mathematical approaches. Some of them (e.g. the "Many Universes" interpretation) is platonic; some of them are just manipulations of classical mechanics (e.g. canonical quantum mechanics).

All in all, it's not a finished theory in my honest opinion, so there is no need to really worry whether it's compatible with Marxism or not.

Relational Quantum Mechanics (http://en.wikipedia.org/wiki/Relational+Quantum+Mechanics) appears to be a fairly materialistic interpretation (considering Smerlak and Rovelli's work on the EPR paradox).

[Janus]

So, I'd really appreciate it if some would give me a simple explanation of quantum physics?
You'd probably want to be somewhat familiar with basic physics before you tackle quantum physics. However, if you have any specific questions you can check out this physics forum: http://www.physicsforums.com/

[RebelDog]

All in all, it's not a finished theory in my honest opinion, so there is no need to really worry whether it's compatible with Marxism or not.

I don't think anybody could say its a finished theory. We need a quantum theory of gravity. That would be nobel winning.

[ComradeRed]

Originally posted by The [email protected] 28, 2007 07:57 pm

All in all, it's not a finished theory in my honest opinion, so there is no need to really worry whether it's compatible with Marxism or not.

I don't think anybody could say its a finished theory. We need a quantum theory of gravity. That would be nobel winning.
Well there are a lot of problems with Quantum theory right now, without gravity being quantized.

For example, unitary evolution isn't how systems really work; that's the radical revolutionary result of relativity.

That means that time becomes a parameter, which requires a non-real Hamiltonian. That's fine and dandy for a few calculational techniques, a sort of heuristic crutch. But it doesn't work as a general case.

That's a serious problem since that basically says "Quantum mechanics breaks down when used properly."

Wuhoh that's not supposed to happen! :o

So, the idea now is that we definately know that quantum theory isn't a final theory since it's not background independent and it can't make proper use of time. There are pushes for the use of topos logic to play a bigger role (well, a role) in quantum theory, and there are pushes for a more relational quantum interpretation of time.

There's going to be some interesting work done in the next few decades; perhaps a "new Einstein" will emerge and "save us all" from the current state of physics with some beautiful math.

[RebelDog]

The new Large Hadron Collider at CERN is the most exciting thing in years;

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

It will surely, over time, give us some answers.

[ComradeRed]

Originally posted by The [email protected] 28, 2007 09:38 pm
The new Large Hadron Collider at CERN is the most exciting thing in years;

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

It will surely, over time, give us some answers.
Not necessarily, because these problems arise in the mathematical limitations of the theory as it stands today in relation to relativity.

There never was a satisfactory marriage of the two, and that needs to be resolved.

The dilemma with quantum gravity is that general relativity needs to be quantized insomuch as quantum theory needs to be "generally relativized".

Of course, there are those (evil bastardly string theorists) who tell us that quantum theory is fine and dandy and that it is merely a "philosophical aside" on making quantum theory background independent. There is much more to it than that in order to quantize gravity (at least canonically).

Just my thoughts on the subject.

[edit] Actually I had the pleasure of going to a colloquiem organized at Caltech with one of the lead researchers of CERN giving the presentation on what they hope to find with the LHC. It was rather interesting as he was overly optimistic about having data within a decade or two.

He hoped to find the graviton and the Higgs boson, by indirect evidence of course through the behavior of other particles (if I can recall correctly from his presentation, I'm exhausted at the moment).

I'll never forget how he never let go of his pointer and had a thick swiss accent.