BUCKYBALLS!

[Vraith]

Surely the 'many worlds' results of the maths of quantum mechanics is just a bizzare by product that tells us that while we might be on the right track, we have a ways to go before we get the thing signed, sealed and delivered. All those infinite infinities multiplying on and on - that has to be an artfact of a problem in the theory somewhere. Doesn't it?

I sure don't know enough for a definitive answer...and I'm fairly sure that right now no one knows enough for that.
After all, we know that some things math tells us cannot possibly be "true" except conceptually/abstractly.
OTOH, we also know that some things that seemed impossible have been predicted by math and turned out not only to be true, but common...even necessary..."physically."
And a huge array of things without math to fully explain them, or math that shows things but no way, even theoretically, [so far] to decide/prove/"see" them.

IF they [the universes] are "real" though, I don't see how we can claim we know the slightest true thing about energy, any more than early metal-workers really knew anything about fire.

[ussusimiel]

Surely the 'many worlds' results of the maths of quantum mechanics is just a bizzare by product that tells us that while we might be on the right track, we have a ways to go before we get the thing signed, sealed and delivered. All those infinite infinities multiplying on and on - that has to be an artfact of a problem in the theory somewhere. Doesn't it?

Not necessarily, but, as Av says, it's not really relevant. Within our own universe, even if we had FTL, simply *says he blithely* travelling to another galaxy would be an incredible achievement. Messing with parallel universes would another order of achievement again.

u.

[Hashi Lebwohl]

I have been interested in the boundary between wave-like and particle-like behavior myself, specifically wondering how large something has to be to have primarily particle-like behavior or how much energy it has to have to display mostly wave-like behavior.

The deBroglie wavelength is given by h/p (Planck's constant divided by momentum) or h/mv (Planck's constant divided by mass*velocity). Kinetic energy is (1/2)*m*v^2 so a little rearraging gives us m*v = 2*k/v which allows us to substitute and get deBroglie = (h*v)/(2*k) where h is Planck's constant, v is velocity in m/s, and k is kinetic energy. I am looking for a good relation between kinetic energy and temperature to show that the colder something gets the lower its kinetic energy and thus the larger its deBroglie wavelength will become.
Ideally, at some temperature--or some combination of mass and kinetic energy--we should be able to find a situation in which the deBroglie wavelength of an object is greater than or equal to the length of the object itself. When this happens, two particles which are side-by-side would have overlapping wavelengths--the two particles have now become indistinguishable from one another.

I broke down and went to wikipedia, which has actually become a reliable source in the past couple of years. Here is the sub-article on wave behavior of large objects from the general "wave particle duality" article.

Since the demonstrations of wave-like properties in photons and electrons, similar experiments have been conducted with neutrons and protons. Among the most famous experiments are those of Estermann and Otto Stern in 1929.[13] Authors of similar recent experiments with atoms and molecules, described below, claim that these larger particles also act like waves.

A dramatic series of experiments emphasizing the action of gravity in relation to wave–particle duality were conducted in the 1970s using the neutron interferometer.[14] Neutrons, one of the components of the atomic nucleus, provide much of the mass of a nucleus and thus of ordinary matter. In the neutron interferometer, they act as quantum-mechanical waves directly subject to the force of gravity. While the results were not surprising since gravity was known to act on everything, including light (see tests of general relativity and the Pound-Rebka falling photon experiment), the self-interference of the quantum mechanical wave of a massive fermion in a gravitational field had never been experimentally confirmed before.

In 1999, the diffraction of C60 fullerenes by researchers from the University of Vienna was reported.[15] Fullerenes are comparatively large and massive objects, having an atomic mass of about 720 u. The de Broglie wavelength is 2.5 pm, whereas the diameter of the molecule is about 1 nm, about 400 times larger. In 2012, these far-field diffraction experiments could be extended to phthalocyanine molecules and their heavier derivatives, which are composed of 58 and 114 atoms respectively. In these experiments the build-up of such interference patterns could be recorded in real time and with single molecule sensitivity.[16][17]

In 2003, the Vienna group also demonstrated the wave nature of tetraphenylporphyrin[18]—a flat biodye with an extension of about 2 nm and a mass of 614 u. For this demonstration they employed a near-field Talbot Lau interferometer.[19][20] In the same interferometer they also found interference fringes for C60F48., a fluorinated buckyball with a mass of about 1600 u, composed of 108 atoms.[18] Large molecules are already so complex that they give experimental access to some aspects of the quantum-classical interface, i.e., to certain decoherence mechanisms.[21][22] Recently, the interference of molecules as heavy as 6910 u could be demonstrated in a Kapitza–Dirac–Talbot–Lau interferometer. These are the largest objects that so far showed deBroglie matter-wave interference.[23]

Whether objects heavier than the Planck mass (about the weight of a large bacterium) have a de Broglie wavelength is theoretically unclear and experimentally unreachable; above the Planck mass a particle's Compton wavelength would be smaller than the Planck length and its own Schwarzschild radius, a scale at which current theories of physics may break down or need to be replaced by more general ones.[24]

Recently Couder, Fort, et al. showed[25] that we can use macroscopic oil droplets on a vibrating surface as a model of wave–particle duality—localized droplet creates periodical waves around and interaction with them leads to quantum-like phenomena: interference in double-slit experiment,[26] unpredictable tunneling[27] (depending in complicated way on practically hidden state of field), orbit quantization[28] (that particle has to 'find a resonance' with field perturbations it creates—after one orbit, its internal phase has to return to the initial state) and Zeeman effect.[29]

[ussusimiel]

Whether objects heavier than the Planck mass (about the weight of a large bacterium) have a de Broglie wavelength is theoretically unclear and experimentally unreachable...[29]

Thanks, Hashi, that's really cool and interesting. I had a look at some stuff about wave-particle duality but quickly became lost. I can follow most of this.

Any idea what 'experimentally unreachable' means in this context?

u.

[Vraith]

Whether objects heavier than the Planck mass (about the weight of a large bacterium) have a de Broglie wavelength is theoretically unclear and experimentally unreachable...[29]

Thanks, Hashi, that's really cool and interesting. I had a look at some stuff about wave-particle duality but quickly became lost. I can follow most of this.

Any idea what 'experimentally unreachable' means in this context?

u.

It means we haven't got there yet.
That's the number I was talking about earlier...the hard line where we really find out if quantum is possibly bigger [or different might be a better word] than we think.
It's why I said what we know, right now, to advance, depends more on the watchmakers than the time-dreamers.
As I might have mentioned elsewhere...people tend to say about "string theories" the aren't theories, really, cuz you can't test them, so it doesn't MATTER if they are right or not.
But, in the last few years, plumber-class physicists have been saying "hold your horses...we can't BUILD the test yet, but we've figure out how to do the test...eventually. Just like Da Vinci "invented" impossible [then] things. they're not only possible now, they're crappy shit a smart teen can build in his garage.

[ussusimiel]

It means we haven't got there yet.

That's the bit I don't understand 'cos it's not a measurability issue, AFAICS.

Is it that the molecules haven't been created yet and they know that more in the grey area will be sooner or later? That'd fit as they wouldn't yet have the experimental data either side of the dividing line (if there is a clear one).

u.

[Vraith]

It means we haven't got there yet.

That's the bit I don't understand 'cos it's not a measurability issue, AFAICS.

Is it that the molecules haven't been created yet and they know that more in the grey area will be sooner or later? That'd fit as they wouldn't yet have the experimental data either side of the dividing line (if there is a clear one).

u.

heh...If I understand it correctly, not a certainty...
the math has an exact limit where IF we COULD do the experimental test, below that limit quantum effects should apply. Above it, they should not.
However, the problems are multiple. Such a clear line, everything taken to the limits, means the universe itself is in some strange way, inconsistent with itself. [or at least "dual natured"...a cosmic particle/wave analogically, though not "literally."...or maybe "literally," but in a way we may not be able to comprehend any more than a word can comprehend the sentence it is part of, nor the page it is printed on/mouth it is spoken from.]
I'm sure none of that makes any sense at all.

Also, it is in no way certain that the objects necessary to test it can exist naturally [probably not] or even be "manufactured." And if they CAN't,

[pure flight of fancy/speculation ahead! You are WARNED] we're in a situation where the problem isn't that some things remain mysterious, but where EVERYTHING is mysterious forever, except those things that are tedious, mundane, and boring. In that case, eventually [heh...but not any time soon] everything knowable will be known, everything doable will be done, and yet an infinite void will surround us in every possible direction.
A complete and unalterable dead end...without the end, and us not dead [yet].
The only words I can think of that apply to that state are hell and horror.

[Avatar]

Surely the 'many worlds' results of the maths of quantum mechanics is just a bizzare by product that tells us that while we might be on the right track, we have a ways to go before we get the thing signed, sealed and delivered. All those infinite infinities multiplying on and on - that has to be an artfact of a problem in the theory somewhere. Doesn't it?

Not necessarily, but, as Av says, it's not really relevant. Within our own universe, even if we had FTL, simply *says he blithely* travelling to another galaxy would be an incredible achievement. Messing with parallel universes would another order of achievement again.

I just meant it doesn't matter if there is some other version of me doing something else, somewhere else. I'm here doing what I'm doing, and that's all I can do. That other version isn't actually me. I'm me. Since the chances of ever interacting with some parallel universe with another version of everything in it is so infinitesimally small, and we live (by default) as though this were the only version, (which it is to us), the others might as well not exist, even if they did.

Ha.

--A

[Hashi Lebwohl]

Any idea what 'experimentally unreachable' means in this context?

u.

It probably means that they don't know yet how to design an experiment to test for this, at least not one that might give reproducible or conclusive results.

Some interesting things have been happening with supercooled materials in the last decade or so, which have resulted in being able to see quantum behavior expressed at macro level. There won't be one clear line that separates quantum from classical behavior; it will depend upon the material in question, how it is put together, its temperature/energy state, etc.

This line of experimentation is probably the most likely to give us room-temperature superconductors that are cost-effective to manufacture.

[ussusimiel]

In that case, eventually [heh...but not any time soon] everything knowable will be known, everything doable will be done, and yet an infinite void will surround us in every possible direction.
A complete and unalterable dead end...without the end, and us not dead [yet].
The only words I can think of that apply to that state are hell and horror.

There, now! Calm down! (about 30 sec in)

Must be a bit of a nightmare alright for a diehard materialist The idea of the unknowable or the void


For us dualists this is not a biggie. We know that some stuff is just unknowable and because some part of us is immortal it's not so scary.


*smug shit-eating grin* (patented)


u.

[Vraith]

In that case, eventually [heh...but not any time soon] everything knowable will be known, everything doable will be done, and yet an infinite void will surround us in every possible direction.
A complete and unalterable dead end...without the end, and us not dead [yet].
The only words I can think of that apply to that state are hell and horror.

There, now! Calm down! (about 30 sec in)

Must be a bit of a nightmare alright for a diehard materialist The idea of the unknowable or the void


For us dualists this is not a biggie. We know that some stuff is just unknowable and because some part of us is immortal it's not so scary.


*smug shit-eating grin* (patented)


u.

Heh...I liked that little vid.

But my problem isn't that some things are/remain unknowable/mysterious [or at least ineffable]...that's fun and interesting.
What I don't like is the other part...the knowing of all knowable.
It's not the void out there, its being a full cup.
Not that "we can't know everything."
But that we CAN.

[peter]

Got to be carefull here because I'm on rich turf for making a fool of myself, but David Deutsch in his book 'The Beginning of Infinity' (which I have mentioned in these pages before) believes that if the multiple worlds of quantum theory do in fact exist then it will be possible for information to flow between them. I don't think he believed that communication as such would be achieved, just that indirect effects would be percievable in our world that could only result from events in theirs. Granted it's hard to see where this could lead to significant effects in our world, but it might be early in the day to predict too far as to what this knowledge might bring to the table.

[ussusimiel]

Heh...I liked that little vid.

The song is by my favourite Irish songwriter (after Van Morrison, of course) called Pierce Turner (he lives in New York and hangs out with Philip Glass from time to time). John Peel said his song Wicklow Hills was in his Top 10 favourite songs (along with Teenage Kicks by the Undertones). (That's my little plug for popular Irish music done for the day )

It's not the void out there, its being a full cup.
Not that "we can't know everything."
But that we CAN.

I get that. I reckon that if we ever get to that stage we'll have the technology to virtually realise anything we can imagine which basically means that we can journey on and explore indefinitely. (Iain Banks in his novel Excession calls it Infinite Fun!)

u.

[peter]

Will we not then truly be Gods!

[Avatar]

We already are. Also devils and everything in between.

--A