Gelatine substitute - chemistry question

Originally posted by DeepThought
I'll stick to the Copenhagen interpretation of quantum mechanics for this - but note that what I am saying is not true if de-Broglie-Bohm theory is right for example. In the standard theory of quantum mechanics particles exist in linear superpositions of states. This is identical to a soundwave with harmonics. The difference is when an observation of ...[text shortened]... ther true or not true they have to be wrapped up to take account of the superposition of states.

You are using in-house terms and references to ideas which make your text almost unintelligible to a layman. The sound analogy is good, I can understand sound travelling in waves and harmonics which are also present but on a different level, sometimes they can be perceived by the ear and sometimes they are not depending on their frequency. But it appears to come down to states? in that a particle can be in different state at the same time. It makes absolutely no sense to me, sorry, but thanks for trying.

Originally posted by robbie carrobie
You are using in-house terms and references to ideas which make your text almost unintelligible to a layman. The sound analogy is good, I can understand sound travelling in waves and harmonics which are also present but on a different level, sometimes they can be perceived by the ear and sometimes they are not depending on their frequency. But it ...[text shortened]... erent state at the same time. It makes absolutely no sense to me, sorry, but thanks for trying.

Yes they can be in two states at the same time, time sharing particles. But the gist of quantum mechanics is this: If you want to know the location of a particle you can but the more precise you pin down the location the less precise is the amount of energy the particle contains. So if you get the location down to a gnats ass, the particle could mass a trillionth of a gram or it could be a whole gram. Conversely, if you want to know how much energy the particle contains, and you get that defined to within a gnats ass, you don't have a good feel for exactly where it is. That is the uncertainty principle in action, you can't know the exact energy of a particle AND the precise location at the same time. So you end up with a number with circles around it representing a probability it weighs such and such and is in location such and such with that location with windows around it where those numbers can be anything fitting between those window walls, say one something or other plus or minus 1/10th or such so those numbers have wiggle room in them. The more precise you know one aspect, the less precise you know the other.

Originally posted by sonhouse
Yes they can be in two states at the same time, time sharing particles. But the gist of quantum mechanics is this: If you want to know the location of a particle you can but the more precise you pin down the location the less precise is the amount of energy the particle contains. So if you get the location down to a gnats ass, the particle could mass a tril ...[text shortened]... wiggle room in them. The more precise you know one aspect, the less precise you know the other.

ok thanks very much, I understand that, here is my question, Why can you not know precisely where it is yet know how much energy it has? Is it lack of equipment to measure its location? Is it a flaw in our understanding? Does it behave so erratically that its problematic? also when we talk about being in two states at the same time, are we talking about its nature or its location? Is there a dimension that we are unaware of?

Please for give my ignorance as you see I know practically nothing about it and its interesting to have it related in these readily discernible ways using analogy and illustration.

Originally posted by robbie carrobie
ok thanks very much, I understand that, here is my question, Why can you not know precisely where it is yet know how much energy it has? Is it lack of equipment to measure its location? Is it a flaw in our understanding? Does it behave so erratically that its problematic? also when we talk about being in two states at the same time, are we talking ...[text shortened]... interesting to have it related in these readily discernible ways using analogy and illustration.

It is the momentum and position that cannot be known simultaneously. Within the theory it is ontological, the information simply doesn't exist. While our understanding may be flawed, every experiment I know of has confirmed quantum theory. As far as your nature/location question goes, a wave is not a localised phenomenon. A wave with a definite momentum state (a plane wave) extends through the whole of space. A wave with a definite position (imagine a zero-width normal distribution) is a superposition of waves of all possible wavelengths.

Originally posted by DeepThought
It is the momentum and position that cannot be known simultaneously. Within the theory it is ontological, the information simply doesn't exist. While our understanding may be flawed, every experiment I know of has confirmed quantum theory. As far as your nature/location question goes, a wave is not a localised phenomenon. A wave with a definite momen ...[text shortened]... agine a zero-width normal distribution) is a superposition of waves of all possible wavelengths.

As I understand it, quantum physics has been used to develop computers. Normally computers work by switches which are either on or off, represented as you are aware in binary by zeros and ones. Is it the case that because of this 'strange' and almost 'inconceivable' nature of the state of particles that they can be 'on and off' at the same time? so that there is no more just boolean expressions of 'or' but now 'and', e.g 'true and false', 'on and off', existing simultaneously at the same time.

Its really almost impossible to understand.

Originally posted by robbie carrobie
As I understand it, quantum physics has been used to develop computers. Normally computers work by switches which are either on or off, represented as you are aware in binary by zeros and ones. Is it the case that because of this 'strange' and almost 'inconceivable' nature of the state of particles that they can be 'on and off' at the same time? so ...[text shortened]... d off', existing simultaneously at the same time.

Its really almost impossible to understand.

Aye, that it is matey. But such is the true nature of the universe. We are in a quantum world like it or not. I have heard of experiments that put particles not in just 2 simultaneous states but 8. Like having a dude hiding in the hills and an army is approaching and he is firing all the rifles at once and they think an army is up in the hills.

Originally posted by sonhouse
Aye, that it is matey. But such is the true nature of the universe. We are in a quantum world like it or not. I have heard of experiments that put particles not in just 2 simultaneous states but 8. Like having a dude hiding in the hills and an army is approaching and he is firing all the rifles at once and they think an army is up in the hills.

really? is it conceivable that there is some other dimensions that we are unaware of at present?

Originally posted by robbie carrobie
is it conceivable that there is some other dimensions that we are unaware of at present?

The word "conceivable" generally means "able to be imagined".
I doubt we can ever truly 'imagine' a dimension we have never experienced before. That would be like 'imagining' a color we never seen before. We may only 'imagine' an analogy of it, or merely 'imagine' some of its mathematical/physical properties. But that, of course, doesn't imply in any way that such another dimension probably doesn't exist.

Originally posted by humy
The word "conceivable" generally means "able to be imagined".
I doubt we can ever truly 'imagine' a dimension we have never experienced before. That would be like 'imagining' a color we never seen before. We may only 'imagine' an analogy of it, or merely 'imagine' some of its mathematical/physical properties. But that, of course, doesn't imply in any way that such another dimension probably doesn't exist.

I am so out of my depth I cannot contribute anything meaningful to the subject. I apologise for that.

Originally posted by robbie carrobie
really? is it conceivable that there is some other dimensions that we are unaware of at present?

You know about the inverse square law of gravity, right? If you are on Earth and weigh 100 KG like me, if you go up one radius, about 4000 miles up and imagine yourself on a 4000 mile high platform you will weigh 1/4 of Earth surface weight, or 25 Kg. You would be at 2 r, two radius numbers out, on Earth you are at 1 radius number, 4000 odd miles from the center of Earth. So 4000 miles up you are 8000 miles from the center, so inverse of 2 squared or 1/4th.

So scientists are looking for exceptions to that law, up close variations from the inverse square law, so far it has held up down to about 100 microns separation of two masses.

The idea is if there is found an exception to where the inverse square law starts being more linear, not a square function, so that say, at 50 microns you get X attraction and at 25 microns you now get not 4 times the attraction but say just double, that would show a break in the inverse square law at close distances. It gets harder and harder to measure that kind of thing when you get masses closer and closer together but if they actually find variations in the inverse square law, it would represent evidence that there are indeed other dimensions and in this case saying there would be dimensions like a tiny piece of tubing very very tiny but another dimension curled up. So far they have found no variations of the inverse square law so they continue to try to make that measurement at closer and closer distances, so far nothing.

Originally posted by robbie carrobie
As I understand it, quantum physics has been used to develop computers. Normally computers work by switches which are either on or off, represented as you are aware in binary by zeros and ones. Is it the case that because of this 'strange' and almost 'inconceivable' nature of the state of particles that they can be 'on and off' at the same time? so ...[text shortened]... d off', existing simultaneously at the same time.

Its really almost impossible to understand.

Quantum computing is one of those weird fields. For one thing no one is quite sure if it will work. The basic idea is that instead of the classical values of 1 and 0, one can put registers into linear superpositions of these two values. So far I think they've managed to get a register with eight qubits.

Quantum computing entered University syllabuses the year after I did my undergraduate degree, so while I know a lot about quantum theory I don't know much about quantum computing. There's more than one way of doing it and it's also not very clear if it works at all, in the sense of being faster than a conventional computer.