The Secrets of Quantum Physics BBC4

[ferneyhoughgeliebte]

Anyone who thinks they understand the Forum hasn't understood the Forum.

[clive heath]

The rho quantities in the equation are a special kind of correlation coefficient. Correlation coefficients can be negative as shown here

http://www2.webster.edu/~woolflm/correlation/correlation.html

If you want to sort out even more quantum physics with Bells on including the polarisation set-up as on the programme, there's lots on you tube....me, I've got a fridge to defrost. But before I go, how's this for a coincidence?: after contributing to this thread last night, bolstered by about half a bottle of Monthelie white and then more of the same appellation's red (premier cru "Sur La Velle") both from Henri de Villamont, I retired to my bed-time reading and within a page or two came across a discussion of "coupling" in Mendelism with the following categories "purple and grey, no purple and grey, purple and no grey, no purple and no grey". If we make grey =a and no grey =a' etc. and for purple =b, we get the four terms in the puzzling equation. Bizarre.

[Gordon]

Anyone who thinks they understand the Forum hasn't understood the Forum.

A funny thing happened on the way to the Forum....two posters spontaneously disappeared in a puff of logic.

....Now that we've sorted out Quantum Mechanics....

...World Peace? Might be easier.

"This statistical interpretation is now universally accepted as the best possible interpretation for quantum mechanics (quantum theory), even though many people are unhappy with it. People had got used to the determinism of the last century [20th], where the present determines the future completely, and they now have to get used to a different situation in which the present only gives one information of a statistical nature about the future.

A good many people find this unpleasant; Einstein has always objected to it. The way he expressed it was: "The good God does not play with dice". Schrodinger also did not like the statistical interpretation and tried for many years to find an interpretation involving determinism for his waves. But it was not successful as a general method.

I must say that I also do not like indeterminism. I have to accept it because it is certainly the best that we can do with our present knowledge. One can always hope that there will be future developments which will lead to a drastically different theory from the present quantum mechanical theory and for which there may be a partial return of determinism. However, so long as one keeps to the present formalism, one has to have this indeterminism." [1974]

"Just because the results happen to be in agreement with observation does not prove that one's theory is correct" [1987].

P A M Dirac, one of a tiny few that understood QM and its implications - he wrote the definitive mathematical description in the 20s. His views above suggest that he was a sceptic too.

http://www.fulviofrisone.com/attachm...0-%20Dirac.pdf - only for masochists.

A startling thing for me is that as I was doing my electronics degree in the early 60s I was taught QM - just when Bell was forming his ideas!! Salutary to realise that one was alive at the time of the struggle to understand it, a struggle that continues.

[teamsaint]

Anyway. Now that we've sorted out Quantum Mechanics (keep up, Flay!), what's the next problem for the forum?

Not sure, but next time you are getting flak about this forum and its discussions, mentioning that the members sorted out QM before the second BBC prog might be useful ammunition.

Of course, when I say " before", that is making assumptions that might be hard to make stick when we start on space/ time and black hole theory.

Although I understand that black holes ar now not what they were, and event horizons are "apparent".
Apparently.

http://www.nature.com/news/stephen-hawking-there-are-no-black-holes-1.14583

One useful concepts that this throws up, is the idea of an event horizon from which no information can escape, or only in " a more garbled form."

i wonder if this is connected to the R3 website listings in any way?

[Gordon]

I wonder if this is connected to the R3 website listings in any way?....

Well there is a lot of gravity here, strong enough to emulate a BH!!

[ardcarp]

Should the thread title read The Secrets of GCSE Maths? Maybe when episode 2 is screened, we can re-boggle at the delicious counter-intuitiveness of the Quantum world.

[french frank]

Should the thread title read The Secrets of GCSE Maths? Maybe when episode 2 is screened, we can re-boggle at the delicious counter-intuitiveness of the Quantum world.

Don't see why - people couldn't cope with the counter-intuitiveness of a coin that had only one side .

[aka Calum Da Jazbo]

old poppa told me you cannot toss a one sided coin and that you avoid the clap with one handed efforts


[coat on]

[Gordon]

Don't see why - people couldn't cope with the counter-intuitiveness of a coin that had only one side .

At the risk of extending this bizarre subject: a "coin" with one side is, in the normal sense of the object [the pound in your pocket as the man said all those years ago], impossible, the obverse/reverse, even if blank, still exist as pair. The coin may have one surface but only has 3 sides for topographic reasons - the cylindrical side [edge] is much smaller than the two round sides. Melt the coin and let surface tension have its way and you have a spherical object with no edges and only a [solid] inside and a single ouside surface. Blow it like glass to make a hollow balloon of it and you have an inside surface too. Try tossing that. When is a coin not a coin?

However, the example of the Moebius strip may be invoked here - it is a single sided surface with one edge a sort of single sided coin of you allow the coin to be non circular, eg square. Try tossing a Moebius strip. The three dimensional equivalent is a Klein bottle. Google, do.

[french frank]

a "coin" with one side is, in the normal sense of the object

And there you have it.

Actually, I have just watched the relevant bit of the film again. The problem (for me) was not the maths, but the physics - of which I have none. Once it got into the realms of photons, beams and polarization I lost track of the fact that he was talking about the written equation. I heard that he would run the test 4 times, to give 4 measurements and that he would "add them up" [sic]. He then wrote his results one above the other, without the equation:

0.56
0.82
0.59 (minus sign silently removed)
0.56

So, in my Msg #54, adding a+b+c+d the objection at that point SHOULD have been: "But the equation indicates that it's a+b -c+d. Simple.

[Gordon]

........So, in my Msg #54, adding a+b+c+d the objection at that point SHOULD have been: "But the equation indicates that it's a+b -c+d. Simple.

So are we happy now?! Or just not unhappy?

[french frank]

So are we happy now?! Or just not unhappy?

With the maths, happy :-) With the physics, I'll start on Physics for Dummies tomorrow!

[Gordon]

Heads UP - or is that Tails down? - anyway the next and last exciting but mind bogglig episode of the quantum saga is on BBC4 tomorrow at 9PM, that's evening for those in America - and tomorrow is the day after today. This time it's about:

The Secrets of Quantum PhysicsEpisode 2 of 2: Let There Be Life

Physicist Jim Al-Khalili routinely deals with the strangest subject in all of science - quantum physics, the astonishing and perplexing theory of sub-atomic particles. But now he's turning his attention to the world of nature. Can quantum mechanics explain the greatest mysteries in biology?

His first encounter is with the robin. This familiar little bird turns out to navigate using one of the most bizarre effects in physics - quantum entanglement, a process which seems to defy common sense. Even Albert Einstein himself could not believe it. [I trust that no robins are harmed in the making of this programme.]

Jim finds that even the most personal of human experiences - our sense of smell - is touched by ethereal quantum vibrations. According to the latest experiments, it seems that our quantum noses are listening to smells. [That's what I call entanglement]. Jim then discovers that the most famous law of quantum physics - the uncertainty principle - is obeyed by plants and trees as they capture sunlight during the vital process of photosynthesis.

Finally, Jim asks if quantum physics might play a role in evolution. Could the strange laws of the sub-atomic world, which allow objects to tunnel through impassable barriers in defiance of common sense, effect the mechanism by which living species evolve?

So are twins entangled? The idea of people wandering about in a haze of uncertainty and only making decisons when they have to doesn't seem that odd really. And as for twins travelling relativistically....

There was a young fellow called Bright
Who could travel faster than Light
He set off one day
In a relative way
And came back the previous night.

[ardcarp]

Not unrelated is a phenomenon called the Lorentz Contraction. There's a (somewhat lewd) limerick about that one. That apart, it's about measuring an object which is moving away from the observer at a speed approaching that of light.

[french frank]

Different ways of illustrating the same ideas (nice to hear from Clauser and Aspect):

https://www.youtube.com/watch?v=STF0moww_zQ