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Shroedinger said: if you put a cat in a box which is completly isolated from the outside. The cat can breath obviously, that is not the issue, but from the outside there is no method for observing what is going on inside. Ok, well, we put this cat in a box, and we put in with the cat a substance which has exactly a 50% chance of decaying, and IF it decays it will turn into a poison which will kill the cat. Now, is the cat DEAD or ALIVE?

The explaination provided by the Copenhagen Interpretation and that which is accepted by the Physics Community is that the Cat is in both states at the same time. I was also informed that it was not pragmatic to think of the cat in such a way, but that the example is used a mental expercise for students and used to illustrate the interaction of the quantum and the macro.

I understand the correlations of this tought experiment with that of Electron Diffraction, and also how the Electron Diffraction experiments portrays's the electron's wave/particle duality well. HOWEVER, I have one more question.

If the diffraction pattern was modelled by Shroedinger's wave equation, and it is said to represent the probability of all the paths that the electron can take, then isn't it implied that the electron is a particle? I mean if we talk about diffraction as the result of the existance of multiple states at once, then are we not talking about the electron as if it was a particle?

Discuss:
Electron Diffraction and how it relates to Shroedinger's Cat
More interesting ideas and explaination related to the above mentioned topics.

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Yes, I understand much better now what the probability wave is - it's just that, the probability wave. And as VorpalNeko has said, the electron and other elementary particles are just epiphenomena.

How did Weinberg exactly argue that the spacetime manifold is damaging to physics?

[Psst, GTR is General Theory of Relativity ^_~ ... oh, you edited XD]

Poweroutage, if you condemn GUTs not accounting for gravity then you are mistaking your terminology from where I stand. Grand Unification, at least from inside the particle physics approach, only seeks to unite the electroweak force [Glashow-Weinberg-Salam model, it united Quantum Electrodynamics with the weak force by use of Weinberg Higgs mechanism] with Quantum Chromodynamics. They were not supposed to consider gravity, that is some more suited to the "Theory of Everything" label.

I have little time for string theorists at the moment, their heads are in the clouds, a view shared, informally, by John Ellis in a seminar he gave last year. At the moment we are only pushing into the EWKB [Electroweak Symmetry Breaking] energy regime [the LHC will have an centre-of-mass energy of about 14,000 GeV] whereas the Planck scale is up at 10^19 GeV. Again, I speak with my bias, I would prefer more theorists in the particle physics community to work on more particle physics phenomonelogy at lower energy scales so that current theoretical uncertainties are reduced.

Some people are trying to fly before we can even jog.

Turning that around, the multitude of interpretations might each suggest a certain modification.


I'm saying simply this: get used to many mutually contradictory interpretations of QM. They're all observationally equivalent, but not ontologically so.


TOEs.


No argument there.


Yes--general theory of relativity.


In GTR, the metric couples to the stress-energy-momentum tensor T, as can be seen directly from Einstein's field equation. The metric thus evolves dynamically, in turn affecting how the stress-energy-momentum behaves. String theory has no mechanism for this--one assumes a fixed background metric instead. This kind of 'symbiotic' relationship between the metric and matter distribution is such an essential feature of GTR that some (evidently a minority among those actually working on TOEs, however) see this as an indication that string theory has a fundamentally flawed approach to unification.

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OMG that's cute....

Anyways I read (about a year ago so some of the information might be a little off, I'm trying to remember it) a really good book entitled Shrondiger's Kittens. I forgot who wrote it but if you're intrested pick it up, Shrondiger's paradox always was a little freakey in my mind. Anyways the whole premise of Shrondiger's kittens is this:

Take the shrondiger's cat model but put it in a space ship and make two. So there is two cats, put into two spaceships with the deadly set-up with one diffrence. Only one cat will die, however it cannot be determened which cat it will be. Now send the rockets into two opposite directions of the universe and have them travel for months. (Let's assume that the cats can only die by the poison.) One of the rockets crash into a planet with intellegent life. They pop open the hatch and what do they find?

The whole point of this is when they open the hatch and see if the cat is alive or dead (let's just say the cat they see is dead) the cat billions of miles away is automatically alive because the other cat was observed. I think they called it the electron probiblity wave that collapses once one of the cat's is viewed.

Well long story short it goes to say that something exists in the universe because it is observed, before that there is an infinate number of posibilites for where it is and the state that it's in. Essentally the universe exists because the universe is looking in on itself.

If that isn't a headache (but a fun headache at that) I don't know what is.

Schroedinger, Erwin! Professor of physics!
Wrote daring equations! Confounded his critics!
(Not bad, eh? Don't worry. This part of the verse
Starts off pretty good, but it gets a lot worse.)
Win saw that the theory that Newton'd invented
By Einstein's discov'ries had been badly dented.
What now? wailed his colleagues. Said Erwin, "Don't panic,
No grease monkey I, but a quantum mechanic.
Consider electrons. Now, these teeny articles
Are sometimes like waves, and then sometimes like particles.
If that's not confusing, the nuclear dance
Of electrons and suchlike is governed by chance!
No sweat, though--my theory permits us to judge
Where some of 'em is and the rest of 'em was."
Not everyone bought this. It threatened to wreck
The comforting linkage of cause and effect.
E'en Einstein had doubts, and so Schroedinger tried
To tell him what quantum mechanics implied.
Said Win to Al, "Brother, suppose we've a cat,
And inside a tube we have put that cat at--
Along with a solitaire deck and some Fritos,
A bottle of Night Train, a couple mosquitoes
(Or something else rhyming) and, oh, if you got 'em,
One vial prussic acid, one decaying ottom
Or atom--whatever--but when it emits,
A trigger device blasts the vial into bits
Which snuffs our poor kitty. The odds of this crime
Are 50 to 50 per hour each time.
The cylinder's sealed. The hour's passed away. Is
Our p***y still purring--or pushing up daisies?
Now, you'd say the cat either lives or it don't
But quantum mechanics is stubborn and won't.
Statistically speaking, the cat (goes the joke),
Is half a cat breathing and half a cat croaked.
To some this may seem a ridiculous split,
But quantum mechanics must answer, "Tough @#&!
We may not know much, but one thing's fo' sho':
There's things in the cosmos that we cannot know.
Shine light on electrons--you'll cause them to swerve.
The act of observing disturbs the observed--
Which ruins your test. But then if there's no testing
To see if a particle's moving or resting
Why try to conjecture? Pure useless endeavor!
We know probability--certainty, never.'
The effect of this notion? I very much fear
'Twill make doubtful all things that were formerly clear.
Till soon the cat doctors will say in reports,
"We've just flipped a coin and we've learned he's a corpse."'
So saith Herr Erwin. Quoth Albert, "You're nuts.
God doesn't play dice with the universe, putz.
I'll prove it!" he said, and the Lord knows he tried--
In vain--until fin'ly he more or less died.
Win spoke at the funeral: "Listen, dear friends,
Sweet Al was my buddy. I must make amends.
Though he doubted my theory, I'll say of this saint:
Ten-to-one he's in heaven--but five bucks says he ain't."

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