Once you acheive atoms
the outcomes are more along the lines of deterministic.
I'm not so sure aout this. What about superconductors, superfluid helium, semiconductor devices, cosmic rays....
These are all _obviously_ quantum objects, and all macroscopic. Hell, you can't get more macroscopic than the sun, and it's quantum mechanics that keeps it running.
The point is, while you may not have your classic "where is it and how fast is it going?" type situation, quantum rules are the only way to explain these objects.
Heisenberg uncertainty is not the only strange effect here, others show their faces in different situations. Indeed you'll see an uncertainty relation remarkably similar to Heisenberg's if you try to localise a (classical) sound pulse in time and frequency.
I don't think the idea of 0 kelvin matter is really too problematic. It is really shorthand for "If I take the limit at low temperatures of...".
I guess 0 KE has serious problems when it comes to atoms, like you say, because bound particles have discrete energy levels.
But say we took an electron in free space. It can have an arbitrarily small energy, and almost continuity between levels, as close as we can come to a mathematical continuum (ie the real numbers).
All this is fine and all but I have to disagree that entropy is a measure of energy per se, but a measure of the statistical variation of the constituent parts of a system. So if I get my electron and add heaps more of them in identical states I can have an electron beam with as low an entropy as I like, because in some frame they will all be at rest. The problem comes when trying to make this beam.
Although now that I've said that, That's exactly what goes on in lasers (except with photons). I don't think they have zero entropy. I'll have to ask someone about that.
My main problem with the area-entropy relation was that a large crystal would contribute less to the area of the horizon than a much smaller mass of, say, mud (mud being disorganised and all).
This is loosely (sp) analogous to saying:
Throw a deck of cards that are known to be ordered into a black hole.
Now take an identical deck and shuffle them with Perfect Random Shuffler(tm). Then throw them in with the exact same energy.
In case 1 the EH area will increase by less than in case 2 since there will be no entropic contribution from the randomness of the deck.
Although apparently the entropy-area relation has been proven (I checked out the references posted above the parent. thanks dan, by the way).
Oh, and thanks for the physics talk. I find it's only when you have to argue that you clear things up for yourself.
First of all, IAA Physics Student. I was wondering as an aside how entropy makes it's way into all this. If the event horizon diameter is proportional to entropy and I fed a black hole (non-rotating) a chunk of 0 kelvin matter it would not expand. Since it is not rotating there would be no accretion disk, so the chunk I am feeding it would not heat up with friction, and its entropy would remain 0.
Now suppose the chunk I fed it had the same mass as the black hole itself. THen the black hole would have twice the mass with the same event horizon.
The whole point of a war is to impress the other side with your strength..
I'm not so sure it is. The whole point of war, it seems to me, is to destroy your enemy's ability to wage war. Hence the bombing of armaments factories, railways, airfields et al.
Oh, yeah, does it matter how much it costs me to super-duper-replicate an object?
I think gseidman had a very good point here. No matter how good the material efficiency here, there is going to be a fundamental entropic cost associated with any kind of super-duper-replication. So where do we get low-entropy energy from? The power companies, that's where. There's no way out of that.
And the earth's stored energy can't support us for too ever.
So kids, if you want a job for life, I suggest a renewable energy supplier.
The difference here is that you are calculating a probability for _2_ different situations, so:
Every (fair) coin toss has a probability of 1/2
A sequence of coin tosses obeys the binomial distribution. So 2 heads out of 2 tosses has a probability of 1/4.
What you're saying here is that the sequence of results you got had a probability before you started of P(H)*P(T)*P(T)*P(H)*P(H) or whatever your sequence was. However, this is the same as every other 5-toss sequence's probability. The thing is, there are more 5-toss sequences with 2 heads and 3 tails than there are sequences with 5 heads or 5 tails. So the sequence more likely to be seen is that with a more equal number of heads and tails.
And all this has nothing to do with the probability of seeing another heads on the next toss.
Offered by physicist Penrose who says "I'm too stupid to figure out the complexity of the brain, so I'll confound things with mumbo-jumbo physics".
Before you jump to conclusions you should note that every system is a quantum system. That is the whole point of physics; a unified model of the universe. It's not like "an electron is a quantum system and an apple isn't".
A similar argument is that quantum effects are only evident on a small scale or at low temperatures. The freakin computer you're using to read this shifts macroscopic amounts of charge in a way that can only be explained by quantum mechanics. See Nature, 406 p43 for an example of macroscopic quantum superposition.
For the relationship between quantum computation and (classical) Turing machines see Deutsch, 1985 in Proceedings of the Royal Society of London400 (pp97-117). It seems all that "mumbo jumbo physics" may actually play a role in this after all.
To me it seems ridiculous and unimaginative to assume that even though QM is fundamental to the structure of the universe and seems intimately connected to consciousness (google: "Wigner's friend";"Schroedinger's cat";"measurement problem"), consciousness is strictly a classical phenomenon.
If I was going to create a virus (which I'm not--I'm not evil, but it's fun thinking about it), it would parse IE's preferences to get your home address (from AutoFill), and use it to order pizza for you from Pizza Hut's online ordering site. With anchovies.
I take it you're talking about a "weaker" version of the weak nuclear force. I try to keep up with stuff like this but it's the first I've heard of it.
Slashdot Mirror
just read you email + .sig
clever...very clever
Dave
Once you acheive atoms the outcomes are more along the lines of deterministic.
I'm not so sure aout this. What about superconductors, superfluid helium, semiconductor devices, cosmic rays....
These are all _obviously_ quantum objects, and all macroscopic. Hell, you can't get more macroscopic than the sun, and it's quantum mechanics that keeps it running.
The point is, while you may not have your classic "where is it and how fast is it going?" type situation, quantum rules are the only way to explain these objects.
Heisenberg uncertainty is not the only strange effect here, others show their faces in different situations. Indeed you'll see an uncertainty relation remarkably similar to Heisenberg's if you try to localise a (classical) sound pulse in time and frequency.
Dave
There's also lokmail.
You'd probably do well to read this article from counterpane if you want some analysis of web based encrypted email.
Dave
FUNNY
Mod this up
I don't think the idea of 0 kelvin matter is really too problematic. It is really shorthand for "If I take the limit at low temperatures of...".
I guess 0 KE has serious problems when it comes to atoms, like you say, because bound particles have discrete energy levels.
But say we took an electron in free space. It can have an arbitrarily small energy, and almost continuity between levels, as close as we can come to a mathematical continuum (ie the real numbers).
All this is fine and all but I have to disagree that entropy is a measure of energy per se, but a measure of the statistical variation of the constituent parts of a system. So if I get my electron and add heaps more of them in identical states I can have an electron beam with as low an entropy as I like, because in some frame they will all be at rest. The problem comes when trying to make this beam.
Although now that I've said that, That's exactly what goes on in lasers (except with photons). I don't think they have zero entropy. I'll have to ask someone about that.
My main problem with the area-entropy relation was that a large crystal would contribute less to the area of the horizon than a much smaller mass of, say, mud (mud being disorganised and all).
This is loosely (sp) analogous to saying:
In case 1 the EH area will increase by less than in case 2 since there will be no entropic contribution from the randomness of the deck.
Although apparently the entropy-area relation has been proven (I checked out the references posted above the parent. thanks dan, by the way).
Oh, and thanks for the physics talk. I find it's only when you have to argue that you clear things up for yourself.
Dave
First of all, IAA Physics Student. I was wondering as an aside how entropy makes it's way into all this. If the event horizon diameter is proportional to entropy and I fed a black hole (non-rotating) a chunk of 0 kelvin matter it would not expand. Since it is not rotating there would be no accretion disk, so the chunk I am feeding it would not heat up with friction, and its entropy would remain 0.
Now suppose the chunk I fed it had the same mass as the black hole itself. THen the black hole would have twice the mass with the same event horizon.
Seems a bit shady to me.
Dave
The whole point of a war is to impress the other side with your strength..
I'm not so sure it is. The whole point of war, it seems to me, is to destroy your enemy's ability to wage war. Hence the bombing of armaments factories, railways, airfields et al.
Dave
2 freakin minutes and I'm redundant.
You could always use the HURD
Oh, yeah, does it matter how much it costs me to super-duper-replicate an object?
I think gseidman had a very good point here. No matter how good the material efficiency here, there is going to be a fundamental entropic cost associated with any kind of super-duper-replication. So where do we get low-entropy energy from? The power companies, that's where. There's no way out of that.
And the earth's stored energy can't support us for too ever.
So kids, if you want a job for life, I suggest a renewable energy supplier.
Dave
I had a dream similar to this once. Some guy had found a way to see a *new* colour. In the ultraviolet range I think.
I was about to put on the goggles and see this wondrous new colour and I woke up.
Damn
The difference here is that you are calculating a probability for _2_ different situations, so:
What you're saying here is that the sequence of results you got had a probability before you started of P(H)*P(T)*P(T)*P(H)*P(H) or whatever your sequence was. However, this is the same as every other 5-toss sequence's probability. The thing is, there are more 5-toss sequences with 2 heads and 3 tails than there are sequences with 5 heads or 5 tails. So the sequence more likely to be seen is that with a more equal number of heads and tails.
And all this has nothing to do with the probability of seeing another heads on the next toss.
sorry if this is clumsily put
Dave
Oh, come on. This is so freakin clever. Mod this up for christ's sake
Offered by physicist Penrose who says "I'm too stupid to figure out the complexity of the brain, so I'll confound things with mumbo-jumbo physics".
Before you jump to conclusions you should note that every system is a quantum system. That is the whole point of physics; a unified model of the universe. It's not like "an electron is a quantum system and an apple isn't".
A similar argument is that quantum effects are only evident on a small scale or at low temperatures. The freakin computer you're using to read this shifts macroscopic amounts of charge in a way that can only be explained by quantum mechanics. See Nature, 406 p43 for an example of macroscopic quantum superposition.
For the relationship between quantum computation and (classical) Turing machines see Deutsch, 1985 in Proceedings of the Royal Society of London 400 (pp97-117). It seems all that "mumbo jumbo physics" may actually play a role in this after all.
To me it seems ridiculous and unimaginative to assume that even though QM is fundamental to the structure of the universe and seems intimately connected to consciousness (google: "Wigner's friend";"Schroedinger's cat";"measurement problem"), consciousness is strictly a classical phenomenon.
Dave
If I was going to create a virus (which I'm not--I'm not evil, but it's fun thinking about it), it would parse IE's preferences to get your home address (from AutoFill), and use it to order pizza for you from Pizza Hut's online ordering site. With anchovies.
anchovies???
you evil bastard!!
This is not a sarcastic retort
I have a couple of questions:
I take it you're talking about a "weaker" version of the weak nuclear force. I try to keep up with stuff like this but it's the first I've heard of it.
Fascinating...
Any more details would be very welcome
Dave
"Yield, Bitch!!. My e-nose can smell your terror!!"
Can you name one scrupulous company?
I just don't think it happens, how would you justify it to the stockholders?