oktalist said:
I have a few issues with this video:
perfectly understandable, it wasnt made for those already aware of the finer mechanics of QM, nor mainly directly connected to our discussion. But as I said, I was a little pressed for time yesterday.
Ok, so this is talking about classical Newtonian mechanics and the second law of thermodynamics (which is not a fundamental law, only a reflection of the colossal improbability of reaching a low entropy state
Ahh, so we are not talking of classical, but rather statistical thermodynamics. In that case, the second law of thermodynamics is the consequence. And, just as you say, given time of 101000 the current age of the universe, entropy would decrease to zero for the simple reason that energy has certain quanta: there is a minimum unit of energy, that is used for work, thus increasing entropy. That final, last unused quanta of energy will either remain unused, (breaking the 2. law), or it will be used, bringing the universe to maximum entropy. Assuming of course, that universe is a closed system.
is possible. Not that it has anything to do with quantum mechanics.
It has in the sense that the same applies for particles. subatomic particles are simply easier to handle because the amount of required collisions between these subatomic particles is vastly decreased (unlike the billions and billions within the pool-balls).
[qutoe]Again,
virtually zero, not
actually zero. And I contend that actually, the probability of that guy's lookalike existing on another planet somewhere in the universe is actually a significant probability, the universe is so big.[/quote]
So you contend that the propability of finding an equal jerk, with exactly the same order subatomic particles, precisely the same collisions within this jerk and with his surroundings, and macroscopic features (such as memory pathways in the brain) is highly likely?
I think you are severely underestimating the complexity here. WHile the universe is big, it is not
that big to contain virtually another earth in another milky way (because that would pretty much be required), and by the time the propability of that approaches anything even remotely meaningful even in QM sense, the universe will be lacking planets due to the passage of time and lack of new stars being formed.
That is the level of impropability here: the last star will have born died out before the chances of finding an equal person become meaningful.
But it is non-zero, that I grant you. There is simply such a long way from 'non-zero' to 'even remotely possible within the lifetime of a star-bearing universe'.
Isn't each particle with mass constantly "interacting" with every other such particle in the universe by way of the gravitational field?
Quantum gravity is kind of under research still. The different string theories and all that jazz, you know?
Or the graviton. But we still do not know, because of all the forces, gravity gives us the most headache.
But for any particle with an electrical charge, any electrical charge or field sufficient to disturb it would be enough to collapse the wave-function.
But the photon is also a quantum, with no definite position!
Are you therefore saying you've managed to prove why CERN is useless and make up their results?
Because they fire amazingly fast particles against each other. But if their positions are unknown, how can they ever hope to collide
any particles?
Yet they do this consistently. I wonder why?
Because the particle can only occupy so much space. The larger the mass, the less space occupied. So if another particle, with wave-function saying it is within a small area, passes trough another similar area for another particle, the chances of collision are extremely high.
Just because we do not know the
exact position, does not mean we cannot tell a small specific area where the particle is extremely likely to be.
But since we are talking of Henry the Electron, we have other considerations: electric fields, that spread from the electron. The electron itself wanders a larger area than, say... a neutron, but it also a substancial electric field. That electric field affecting another electron would be enough to collapse the wave function for both: a force is excerted, at specific strenght, to both electrons (A's magnetic field affects B, and vice versa), thereby for the duration of the interaction they are both clearly defined both in space and velocity. And once the interaction ceases, they re-establish the wave function, albeit now with different values: their speed and positions were changed by the event. And this
limited uncertainty (they cannot be everywhere in the universe, just somewhere within a confined area) continues until the next interaction: they meet another electron or a proton, collide with a neutron (less likely), meet an actual atom etc...
They both "observed" each other and collapsed each other's wave functions even though neither had a determinate position?
Both had a determinable position,as by their wave-function: the position is simply not invariant. There are areas where the possibility of them being is higher, and if the propabilities for both pan out when their wave-functions meet, a collision happens.
Mind you, this doesn't happen every time.
Rather, it goes something like this:
Their wave functions produce an interference pattern which is the wave function of the combined two-particle system.
And part of this interference pattern is that they
do collide. As you say, there is a non-zero possibility. They do potentially occupy the same space-time coordinates at the same time.
Just as a single electron fired trough the double-slit experiment interferes with itself.
Now scale that up to a many-particle system like a cat, or that [del]jerk[/del] musician from the video. Put the cat in a box, open and close the box 1010100 times and on the 1010100+1th time, find that it has turned into a dog, because that is one of the possible states in which its electrons and quarks can arrange themselves.
Ahh, no. Why? Because of the internal complexity: there is not a single moment when
all the particles that make up the cat, or even the majority of them, are within a state of superposition. Why? Atoms, surrounded by electrons making complex molecules tied to each other, in long chains. Cells, using meterials and producing energy, electrical charge in the brains of the creature as thoughts arise and die.
Even if it were dead, there would still be trillions and trillions of collisions and collapsing wave functions each second.
There is a reason why the Quantum mechanics applies only the the world of the very small: Individual subatomic particles are not bound invariably by forces to other particles.
One of the more influential things QM can do at atomic level, is quantum tunneling an electron out.
There is almost nothing QM can do at molecular level: too many interactions, strong and weak forces, electrical forces all over the place.
DNA alone, in a single cell, contains 10,000 to 1,000,000,000 base pairs
per chromosome - The chances of DNA changing by QM into that of another species alone is so small as to be accurately described (as my physics prof put it) as 'Infinity minus one to one against.'
Matter itself would cease to exist before a cat changes into a dog. So if you want to talk of something like that as 'possible' then sure, there is a non-zero propability of it happening.
Still doesn't mean it would happen, even if given million times the lifetime of the entire universe from Big Bang to whatever end there is.
