h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

hello hello

is there anybody out there?

bling bling

hello

Hell hasn't visited us for a few weeks, dave. Just be patient

"Patience is a virtue...rarely found in humans, never in a duck!"

Oh well, here I am trying to discuss the next big physics breakthrough, and everyone decides to step out for a couple weeks. Where are all those crazy physics nuts when you need them?

Not Bell's Theorem?

That's what I'm talking about. I think we need to discuss bell's inequality. It basically closed the door on hidden variable theorems.

Yes, I read about it and other stuff about quantum mechanics - seems like physics is coming ever closer to a Buddhist world view! I'm *not* a Buddhist, I hasten to add!

except for the fact that the buddhists never predict anything, and never use numbers, yes, their views are almost identical to physicists.

Well another 3 weeks passes. Its getting kind of lonely around here. Did some sort of zombie plague destroy the british isles and continental Europe while I wasn't looking?

btw

I love the british isles. Never been there, but...man. What a great place. What tradition. I salute you, UK!

dave

ps. actually, I have been there, once. I had a layover in Heathrow on my way to Paris. But that would be lying if I actually used that to claim I'd been to the Isles.

but again, my hat (figuratively) off to you, UK!

dave

I think Hell is in Brazil at the moment. I know he's not around much. I know he had the intention of coming back to this entry ... no indication of when, though!

And at the moment, it's sunny in the British Isles - that crisp autumn sunshine. Cold if you're not in the sun.

I'm glad to hear Hell got to visit Brazil, I hope its for vacation. thank you for the update!

It's sunny in Boston these last couple days, pretty warm too. But that won't last long...

Not sure. Think he may have gone back there to live.

He told me he was originally from Brazil, but that he was working on his Ph.D. in Germany. I hope everythings OK. Hope for the best I guess.

is it possible that the photons are in fact made up of a material even smaller that nobody knows about yet? that is, there may be another internal factor which we don't understand anything about yet. secondly, what proof is there that the particle exists in both states A and B until it is looked at? if it waits until it is seen then how do you know without seeing it? how is it possible to say that the particle is neither A nor B until the moment it is seen? is it that the particle is seen to change? and if so what evidence is there to suggest that this external factor caused the change? And what elements of the intrusion cause the particle to make it's decision to change? I propose that a way be found to detect the status of a particle WiYHOUT the particle KNOWING. if this could be done, it would be able to be observed and studied through each step. but until then i ask you this, can you please, in your entry, write a summary IN ONE SENTENCE what the ERP paradox Is? if not possible well, thanks anyway.

good questions, all, Let me address what I think I can.

First, "Is it possible that the photons are in fact made up of a material even smaller that nobody knows about yet?"

This is akin to the "hidden variables" theorems. These were attempts to come up with variables that had as yet to be observed, which would make QM an exact science. Bell's inequality disproved all these in one fell swoop - so in one sense the answer is no, the photons are not made up of anything smaller. Then again, there is also the small matter of string theory, which does propose the existence of strings whose vibrations are the basis for everything. But the net result of string theory still yields the same results for photons - it doesn't give us any more accuracy in the prediction of state A/B.

Second " if it waits until it is seen then how do you know without seeing it? ". Excellent point. That's the whole mystery right there. Since we see both A&B coming out, and there is no way of proving (for an individual photon) which one it will be, we take it as proven that each one must be both A & B.

Third "is it that the particle is seen to change?" The particle is not seen to change...the change implies you know the initial and final state of the particle, but we only know that the initial is a mix of A & B

"I propose that a way be found to detect the status of a particle WiYHOUT the particle KNOWING" This is just not possible (so far). People have tried this for a very long time. But you're welcome to add your efforts to the cause.

dave

you state: "the change implies you know the initial and final state of the particle" in other words, you do not know the initial state.
So how on earth could you possibly "know that the initial is a mix of A & B"? Has it been proven in any way that the particles do not tear apart from each other and take the forms of 'a' and 'b' as they seperate? Because my impression from your article is that they do not take this form UNTIL you look at them.

My statement was referring to this initial statement that you posted:
"is it that the particle is seen to change?"

I said, no, if we had seen the change, that would mean we knew the initial state. We don't know the initial state. Knowing the initial state means you know whether or not the particle is A or B.

Not knowing the initial state means knowing that the particle has some probability of being A, and some other probabilitiy of being B - this is called a "mix of A & B". So when I say we know that the particle is a "mix of A & B" I'm saying we don't know whether it is A or B, just that we know the probability distribution that we will observe when we make the measurement - we know the probability of the measurement being A, and the probability of being in state B.

Secondly:
the particles are always measured as individual particles, no matter where along the flight path you place the detector. This has been taken to mean that there is no "pre-particle" which then separates into particles A&B.

Lastly:
There are two different types of mearurements you can make. You can determine which state the particle is in, or you can just simply measure the exisitence of the particle. According to conservation of energy & mass, you should get a measurably different observation if there were two particles that at some point split apart. This can be measured independently of determining which state the particle is in.

Also, this isn't my article. It's by HELL, who has temporarily not around. I'm just pinch hitting.

dave