The Universe is Deterministic

[Ziggurat]

What if your only goal was to get the particle on Mars to react instantaneously by measuring its twin on Earth, no Bob necessary. You dont care what the results of your measurement is, only that there is a reaction. Could that be used as a control circuit?

No. As I already mentioned, you can only choose whether or not to do the measurement, you can't choose the outcome of the measurement. And while that determines the outcome of any measurement that might take place on mars, if can't MAKE a measurement happen on mars, and since your measurement's outcome is random, so is the outcome on mars. There's no way, even in principle, that anyone on mars can even determine that you performed a measurement until they get a signal from you (propagating at light speed) to tell them that.

So you are saying its kind of like one of those Klein bottles?

No. For a finite (closed) universe, it's like the surface of a sphere whose radius starts at zero and gets bigger over time. The CMB would be photons racing around the surface of the sphere, since the universe is transparent, they'll just keep racing around forever until the universe collapses. For an infinite universe, well, it's infinite, so it doesn't matter how far away you look, you'll never see the end, so the CMB will persist forever.

And that when we look at early galaxy photons we are looking at photons that have "wrapped around"?

In a closed universe, photons might eventually wrap around, but the universe appears to be too big for photons to have already wrapped around (you can test this by looking for mirror, or ghost, images of distant galaxies in the opposite direction from where you observe them).

 

[LordoftheLeftHand]

What if your only goal was to get the particle on Mars to react instantaneously by measuring its twin on Earth, no Bob necessary. You dont care what the results of your measurement is, only that there is a reaction. Could that be used as a control circuit?

I image your scene would go like this. We send an entangled electron to Mars to be hooked up to a machine. The machine will watch this electron and when it changes it will turn on. Spaceship with the electron makes it to Mars. They unload the electron and are ready to to put it into the machine. But wait a minute. How is this machine going to tell if the electron changes? The only way to tell is to measure it now, then measure it again later to see if there is a change. We set the machine to measure the electron every hour and to toggle itself on or off if there is a change. We load in the electron, the machine measures it and finds its spin is up in the x axis. That means its partner on Earth is certainly down in the x axis. So every time they measure the one on Earth it will be down and every time the one on Mars gets measured it will be up. By measuring the initial condition of the one on Mars, we ruined the pair. Every hour the machine on Mars makes a measurement and finds the electron up. The machine never toggles itself on or off.

 

[Zeuzzz]

Humans beings (and all conscioues entities mind you) prove that the universe is entirely not deterministic and predicated on conscious processes.

Free will is certainly not an illusion. As I have gone into in other threads (the "robot consciousness" thread being one)

 

[shuttlt]

not non deterministic

Is this the same as deterministic?

 

[Zeuzzz]

Shutit shuddlt

Editted.

 

[sol invictus]

Humans beings (and all conscioues entities mind you) prove that the universe is entirely not deterministic and predicated on conscious processes.

Nonsense.

Free will is certainly not an illusion.

As far as I know you're an electric universe bot written to spam internet fora, so why should I believe anything "you" say about free will?

 

[Tumbleweed]

I image your scene would go like this. We send an entangled electron to Mars to be hooked up to a machine. The machine will watch this electron and when it changes it will turn on. Spaceship with the electron makes it to Mars. They unload the electron and are ready to to put it into the machine. But wait a minute. How is this machine going to tell if the electron changes? The only way to tell is to measure it now, then measure it again later to see if there is a change. We set the machine to measure the electron every hour and to toggle itself on or off if there is a change. We load in the electron, the machine measures it and finds its spin is up in the x axis. That means its partner on Earth is certainly down in the x axis. So every time they measure the one on Earth it will be down and every time the one on Mars gets measured it will be up. By measuring the initial condition of the one on Mars, we ruined the pair. Every hour the machine on Mars makes a measurement and finds the electron up. The machine never toggles itself on or off.

Lets start at the beginning. I have two entangled particles one on Earth and one on Mars. Then without any care about actual measurements or electromagnetic communication, I do something to the Earth particle. That in turn causes a reaction to the particle on Mars, right? We DO NOT measure the one on Mars to see its condition at any time. All I care about is that the Mars electron reacts, that the electron changes, due to my actions here on Earth. An analogy would be two syncros. If I cause one to move another will respond. If that syncro was hooked to a paddle that stirs water, that in turn turns on a circuit, it would make no difference what the position the synchro is in initially or ever, only that if it changes position it will stir water. In the case of entangled particles, that would be instantaneously

 

[ben m]

Lets start at the beginning. I have two entangled particles one on Earth and one on Mars. Then without any care about actual measurements or electromagnetic communication, I do something to the Earth particle. That in turn causes a reaction to the particle on Mars, right? We DO NOT measure the one on Mars to see its condition at any time. All I care about is that the Mars electron reacts, that the electron changes, due to my actions here on Earth.

Yes, the Mars electron "reacts" instantaneously. The "reaction" is that the electron changes from a state which has a 50-50 chance of being A or B, into a state which has 100% chance of being the opposite of whatever its Earth partner is ... which, as it turns out, gives it a 50-50 chance of being A or B.

Do you see why no information can be transmitted?

 

[Humanzee]

Thats the part that tosses me a loop ben_m and forgive my lurker stupidity but when you measure the electron on earth doesn't something happen to the electron on mars? Cant the underpaid grad student on mars know when his professor on earth has measured the entangled electron there?
I know I am missing something here.

 

[Tumbleweed]

Yes, the Mars electron "reacts" instantaneously. The "reaction" is that the electron changes from a state which has a 50-50 chance of being A or B, into a state which has 100% chance of being the opposite of whatever its Earth partner is ... which, as it turns out, gives it a 50-50 chance of being A or B.

Do you see why no information can be transmitted?

It sounds like your making it a statistical or probability wave function rather than a physical particle reality and that physically changing one entangled particle does not actually physically change the other ( as with syncros), it only predicts with certainty what the other actually is, spin wise

 

[ben m]

Thats the part that tosses me a loop ben_m and forgive my lurker stupidity but when you measure the electron on earth doesn't something happen to the electron on mars? Cant the underpaid grad student on mars know when his professor on earth has measured the entangled electron there?

No, the grad student on Mars cannot tell what, if anything, has happened on Earth. The only way the Mars observer can interact with this electron's spin is by collapsing its wavefunction. Collapsing the wavefunction does not tell you whether you are collapsing from a pure state or from a superposition. Unfortunately for sci-fi authors, the Earth-measurement's only effect is on exactly the one thing you can't measure---taking a measurement on Earth snaps the Mars particle out of its superposed state and puts it in a pure state. But this is utterly undetectable to you.

 

[Tumbleweed]

And what about quantum tunneling. From what I've read its what causes hydrogen atoms to fuse into helium, a process that conventional physics will not allow. Could things be escaping a black hole due to quantum tunneling? That supposedly is not allowed either. How about escaping Earth's gravity without enough oomph to do so? Would a certain number of rockets make it anyway due to quantum tunneling? Okay, bad analogy, right?

 

[Humanzee]

"Collapsing the wavefunction does not tell you whether you are collapsing from a pure state or from a superposition."

Thank you.

I'll go back and reread the thread then continue my lurking. Thanks for explaining things. Gotta love this forum.

 

[ben m]

And what about quantum tunneling. From what I've read its what causes hydrogen atoms to fuse into helium, a process that conventional physics will not allow.

If by "conventional" you mean "classical"---well, you're making a huge hash out of things if you attempt to describe nuclear bound states classically at all. If you imagine that pseudo-classical fusion requires two protons to get past a hard distance threshold, then yes, classical mechanics translates this hard distance threshold into a hard velocity threshold. In quantum mechanics, these cutoffs are soft and probabalistic.

In any case, quantum mechanics IS conventional physics. Everything we've discussed on this thread is standard textbook material for undergraduate physics and chemistry majors.

Could things be escaping a black hole due to quantum tunneling? That supposedly is not allowed either. How about escaping Earth's gravity without enough oomph to do so? Would a certain number of rockets make it anyway due to quantum tunneling? Okay, bad analogy, right?

Tunneling out of a black hole: sure, that's allowed, it is called Hawking radiation. "Tunneling" out of Earth: sorry, totally different. The point of tunneling is that you can get from a high-energy state to a low-energy state, even if there's an energetically-inaccessible state between the two. A rocket ship on the ground is already a low energy state; getting it away from Earth raises its energy. (Hawking radiation is a special case.

A better example: a rocket ship could (if we ignore enough of the details to focus on the principle) vanish from the Earth's surface and reappear near Jupiter; being deep in Jupiter's gravity well would be a lower-energy state and that's the sort of thing that tunneling does.

 

[Dancing David]

"Collapsing the wavefunction does not tell you whether you are collapsing from a pure state or from a superposition."

Thank you.

I'll go back and reread the thread then continue my lurking. Thanks for explaining things. Gotta love this forum.

I agree but some parts of this lecture I have to review :boggle:

 

[sol invictus]

No, the grad student on Mars cannot tell what, if anything, has happened on Earth. The only way the Mars observer can interact with this electron's spin is by collapsing its wavefunction. Collapsing the wavefunction does not tell you whether you are collapsing from a pure state or from a superposition.

Minor quibble: the state under discussion here is pure, but entangled. All states can be written as superpositions (or not), that just depends on the basis.

taking a measurement on Earth snaps the Mars particle out of its superposed state and puts it in a pure state.

That was the prevailing view for many years, but I think many - perhaps most - physicists today no longer subscribe to it. Quantum field theory is local, and in QFT no such instantaneous, non-local "snap" happens. So unless there's some as yet unknown law of physics, that's not the correct description.

The correct description is that the detector's wavefunction splits into two pieces, one of which measures spin up and the other spin down, like this:

00(ud-du) ---> 0(Dud-Udu) ---> UDud-DUdu.

To explain that cryptic notation, this is an entangled EPR pair being measured in a frame where the right-hand particle is measured first, then the left hand particle. Capital letters are detector states, lower case are particle states, in this order: (DETECTOR ON THE LEFT)(DETECTOR ON THE RIGHT)(particle on left)(particle on right). O means neutral, U means detector measured spin up, etc.

There's no "snap", no instantaneous effects, and everything happens locally.

 

[Tumbleweed]

One more grasp attempt. All this entangled particle thing means is if you measure one, it pinpoints what the measurement of the other must be. Measuring here takes away probability elsewhere and turns it into a specified created reality.
Back to pi and its indeterminate nature. If I cut a string and define its length as either the diameter or circumference of a circle there is no way that I can cut a string to get an exact complimenting circumference or diameter. It seems to be the opposite of entangled particles There, if I measure one the other becomes certain. But with pi, if I measure one the other "entangled through pi" element becomes indefinite. In one, determining determines, in the other determinism leads to indeterminatism

 

[Tumbleweed]

Question: Once the spin of entangled particles are known, can they be changed?

 

[ben m]

One more grasp attempt. All this entangled particle thing means is if you measure one, it pinpoints what the measurement of the other must be. Measuring here takes away probability elsewhere and turns it into a specified created reality.

I wouldn't object if I saw that in the New York Times. It's not quite right but it's in the ballpark.

Back to pi and its indeterminate nature. If I cut a string and define its length as either the diameter or circumference of a circle there is no way that I can cut a string to get an exact complimenting circumference or diameter. It seems to be the opposite of entangled particles There, if I measure one the other becomes certain. But with pi, if I measure one the other "entangled through pi" element becomes indefinite. In one, determining determines, in the other determinism leads to indeterminatism

No, that's all wrong. First, entanglement is very, very specifically quantum-mechanical---that indeterminism, if any, is the carefully-defined indeterminism of wavefunctions.

There's nothing mysterious or unknown about the value of pi; the fact that pi is irrational has practical implications---what steps do you have to follow to make a mark at Pi meters on your measuring tape---but no underlying problems whatsoever. Any such problems are unlikely to be well-described as "indefinite" or "undetermined".

 

[Tumbleweed]

If I take 1/3x 12 I get a definite number. BUT if I divide 1 by 3 FIRST and then multiply by 12, I get an indefinite number. Definite/ indefinte - merely a matter of math choice?