Quantum theory

[David90]

Here's a good question from the novel "Solar" by Ian Mcewan: Is the strange reality described by quantum mehanics a description of the actual world, or is it simply a system that happens to work ?

[Clanad]

In its present state (barely having been born) quantum theory is as much metaphysical as it is science or reality. But, isn't that true of most all scientific advancements? In the past some, if not most, actually believed the Earth to be a flat disk. That, however, was only because of their limited power of observation. Held in the light of today's knowledge that seems absurdly archaic.
"In quantum theory, photons and other particles do not have definite values for properties such as location or polarization but rather acquire a specific property randomly when measured in an experiment". (Source: Scientific American). In fact,as it stands, the mere observation or experimentation of quanta level physics somehow limits its explanation. Its state of "being" (reality, if you wish) is somehow determined by the act of observation. Most physics scientists are grappling with the actual meaning of the term "reality'...

[beso]

Quantum Mechanics is the most successful physical theory of all time. No matter how bizarre the implications of its predictions every one of them has been shown through experiment to be absolutely correct. This is the fundamental premise of the test of the validity of a scientific theory.

Objects have been demonstrated to be in two places at the same time. Objects have been shown to be simultaneously vibrating and stationary. Although traditionally only evident at very small scales, work is continuing to demonstrate Quantum effects on larger and larger objects and a lot of progress has been achieved. There is actually no theoretical reason why these same Quantum effects cannot ultimately be manifested at a macroscopic scale and such a demonstration is the Holy Grail of Quantum research.

Quantum Entanglement has been found to be critical in biological processes such as the magnetic vision of birds. It has just been discovered that Quantum Entanglement of the electrons in the DNA molecule is responsible for the folding of DNA.

[beso]

The "Superposition of Quantum States" is the term used to refer to the ability of an object to simultaneously have multiple otherwise rationally incompatible properties such as being in two places at once.

The implication is that the concept of a particle as we know it is merely an artifact of observation. Reality is (and only is) the interaction of Quantum Wave Functions. Nothing is really solid. Everything, even in the macroscopic world, is a set of wave functions.

There are no particles at all. Superposition does not really occur. The Wave/Particle Duality of light is not duality at all. There is no photon. The perception of the particle is due to the iteraction between the wave function of the quantum object and the wave function of the observer.

Spooky stuff that even those who work in the field are struggling to accept.

[jake-the-peg]

That is a very pertinent and possibly unknowable question.

Quantum theory itself has nothing to say on the issue. It merely allows you to calculate (very accurately) the result of experiments.

However people don't like this - they have in their minds the notion of cause and effect - a notion of the "real world".

People have a need to see the world working in the microscopic scale in the same way as it does in their everyday lives - when it refuses to do so they get upset and insist that it cannot be the complete answer.

The reason that we think that electrons can't be in the same place at the same time is because we don't see busses and cars and everything else able to do it.

The secret is to realise that you have to set aside your intuition that you've built up from decades in the big world and start again.

There are numerous "answers" to this they are called "Interpretations" of quantum mechanics - Copenhagen, many worlds are just two - if you look for interpreations of quantum mechanics on Wikipedia you'll find them and many more.

It is however very unlikely that we'll ever be able to construct an experiment to determine which is right so for me this is one of those games that Mathematicians and theorists get up to when there are no experimentalists around to keep them on the straight and narrow

[Old_Geezer]

A system that hapens to work is a good description of just about everything we think we know. But we trust that it happens to work because it describes whatever is really going on, until a better more refined theory comes along.

[Count-A-Strong]

Although i cannot join in on any meaningful level, this 'stuff' makes the hairs on the back of my kneck stand up! Amazing. I kind of understand the Schrodingers cat principle and wish my brain had the power to extrapolate the theories but alas quantum entanglement (or God as it's sometimes known) saw fit to fold my DNA into a shape which precludes my brain to favour the arts rather than science. Probably why i like science fiction so much (a meeting of the two).

[Count-A-Strong]

I know Kneck (neck) tut.