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Can someone explain?

dylancatlow
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3/9/2015 11:19:53 AM
Posted: 1 year ago
Can someone explain why the prevailing interpretation of quantum mechanics seems to require that the universe systematically violate the identity principle of logic, when such an account is totally unnecessary for explaining what we observe? Why must we rely on logically absurd "mixed states" - states which simultaneously have many values - when we can simply describe such states as having many potential values, and put off ascribing it a "definite" or actualized existence until it has actually been implicated in observation? No law of mutual displacement is in effect among potential states (only actual states).
Burzmali
Posts: 1,310
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3/9/2015 1:30:58 PM
Posted: 1 year ago
At 3/9/2015 11:19:53 AM, dylancatlow wrote:
Can someone explain why the prevailing interpretation of quantum mechanics seems to require that the universe systematically violate the identity principle of logic, when such an account is totally unnecessary for explaining what we observe? Why must we rely on logically absurd "mixed states" - states which simultaneously have many values - when we can simply describe such states as having many potential values, and put off ascribing it a "definite" or actualized existence until it has actually been implicated in observation? No law of mutual displacement is in effect among potential states (only actual states).

The way it has been explained to me is that this is most practical way to have the math worked out, and nothing is treated like it is actually in both states at the same time. That's why these types of scenarios are referred to as wave functions. Just like in math, where you might have f(x) = mx + b and f(z) = z^2 - c, if you need to express a third function that adds both of those, then it's represented as f(x) + f(z). f(x) and f(z) represent all possible results of those equations, but no one is pretending that any individual measurement would result in all values at once. So in quantum mechanics, since you don't know the state of something like a photon until it's measured, it's represented as a function.

Incidentally, the Schroedinger's Cat analogy was an attempt to show exactly what you're talking about: the absurdity of seeing parts of a system as being in multiple states at the same time. But people don't understand that and instead talk like a stereotypical pothead, saying things like "the cat's both alive and dead, man. Whoa!"
dylancatlow
Posts: 12,245
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3/9/2015 1:35:55 PM
Posted: 1 year ago
At 3/9/2015 1:30:58 PM, Burzmali wrote:
At 3/9/2015 11:19:53 AM, dylancatlow wrote:
Can someone explain why the prevailing interpretation of quantum mechanics seems to require that the universe systematically violate the identity principle of logic, when such an account is totally unnecessary for explaining what we observe? Why must we rely on logically absurd "mixed states" - states which simultaneously have many values - when we can simply describe such states as having many potential values, and put off ascribing it a "definite" or actualized existence until it has actually been implicated in observation? No law of mutual displacement is in effect among potential states (only actual states).

The way it has been explained to me is that this is most practical way to have the math worked out, and nothing is treated like it is actually in both states at the same time. That's why these types of scenarios are referred to as wave functions. Just like in math, where you might have f(x) = mx + b and f(z) = z^2 - c, if you need to express a third function that adds both of those, then it's represented as f(x) + f(z). f(x) and f(z) represent all possible results of those equations, but no one is pretending that any individual measurement would result in all values at once. So in quantum mechanics, since you don't know the state of something like a photon until it's measured, it's represented as a function.

Incidentally, the Schroedinger's Cat analogy was an attempt to show exactly what you're talking about: the absurdity of seeing parts of a system as being in multiple states at the same time. But people don't understand that and instead talk like a stereotypical pothead, saying things like "the cat's both alive and dead, man. Whoa!"

I'm glad that you understand this, but I'm afraid many scientists do not. Are you familiar with many-valued logic?
bossyburrito
Posts: 14,075
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3/9/2015 2:03:48 PM
Posted: 1 year ago
But it's science, man. You can't argue against science.

In other news, magic is absurd, right guys? So unscientific.
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dylancatlow
Posts: 12,245
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3/9/2015 2:12:43 PM
Posted: 1 year ago
At 3/9/2015 2:03:48 PM, bossyburrito wrote:
But it's science, man. You can't argue against science.

In other news, magic is absurd, right guys? So unscientific.

Oh, I must have forgotten.
Burzmali
Posts: 1,310
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3/9/2015 2:19:46 PM
Posted: 1 year ago
At 3/9/2015 1:35:55 PM, dylancatlow wrote:
At 3/9/2015 1:30:58 PM, Burzmali wrote:
At 3/9/2015 11:19:53 AM, dylancatlow wrote:
Can someone explain why the prevailing interpretation of quantum mechanics seems to require that the universe systematically violate the identity principle of logic, when such an account is totally unnecessary for explaining what we observe? Why must we rely on logically absurd "mixed states" - states which simultaneously have many values - when we can simply describe such states as having many potential values, and put off ascribing it a "definite" or actualized existence until it has actually been implicated in observation? No law of mutual displacement is in effect among potential states (only actual states).

The way it has been explained to me is that this is most practical way to have the math worked out, and nothing is treated like it is actually in both states at the same time. That's why these types of scenarios are referred to as wave functions. Just like in math, where you might have f(x) = mx + b and f(z) = z^2 - c, if you need to express a third function that adds both of those, then it's represented as f(x) + f(z). f(x) and f(z) represent all possible results of those equations, but no one is pretending that any individual measurement would result in all values at once. So in quantum mechanics, since you don't know the state of something like a photon until it's measured, it's represented as a function.

Incidentally, the Schroedinger's Cat analogy was an attempt to show exactly what you're talking about: the absurdity of seeing parts of a system as being in multiple states at the same time. But people don't understand that and instead talk like a stereotypical pothead, saying things like "the cat's both alive and dead, man. Whoa!"

I'm glad that you understand this, but I'm afraid many scientists do not. Are you familiar with many-valued logic?

I think many of the scientists who deal with this stuff are bad at explaining it, rather than not understanding it. That, and the subject itself can be kind of tough to comprehend.

On the many-valued logic thing, no, I'm not very familiar with it. I seem to remember it being mentioned when I took a class on symbolic logic and critical thinking in college, but that was a decade ago.
Mhykiel
Posts: 5,987
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3/9/2015 4:36:36 PM
Posted: 1 year ago
At 3/9/2015 11:19:53 AM, dylancatlow wrote:
Can someone explain why the prevailing interpretation of quantum mechanics seems to require that the universe systematically violate the identity principle of logic, when such an account is totally unnecessary for explaining what we observe? Why must we rely on logically absurd "mixed states" - states which simultaneously have many values - when we can simply describe such states as having many potential values, and put off ascribing it a "definite" or actualized existence until it has actually been implicated in observation? No law of mutual displacement is in effect among potential states (only actual states).

Well I'm not a quantum physicist but I thought the manifestation of superposition is seen in the double slit experiment.
dylancatlow
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3/9/2015 4:48:02 PM
Posted: 1 year ago
At 3/9/2015 4:36:36 PM, Mhykiel wrote:
At 3/9/2015 11:19:53 AM, dylancatlow wrote:
Can someone explain why the prevailing interpretation of quantum mechanics seems to require that the universe systematically violate the identity principle of logic, when such an account is totally unnecessary for explaining what we observe? Why must we rely on logically absurd "mixed states" - states which simultaneously have many values - when we can simply describe such states as having many potential values, and put off ascribing it a "definite" or actualized existence until it has actually been implicated in observation? No law of mutual displacement is in effect among potential states (only actual states).

Well I'm not a quantum physicist but I thought the manifestation of superposition is seen in the double slit experiment.

Observation constantly collapses the wave functions of the light particles producing the pattern. It's not like the pattern is the result of one light particle in all of those places at once. In other words, absence any observation, the light particle behaves like a wave with many different potential trajectories, and once it is observed its actual path is retroactively determined.
Mhykiel
Posts: 5,987
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3/9/2015 5:23:49 PM
Posted: 1 year ago
At 3/9/2015 4:48:02 PM, dylancatlow wrote:
At 3/9/2015 4:36:36 PM, Mhykiel wrote:
At 3/9/2015 11:19:53 AM, dylancatlow wrote:
Can someone explain why the prevailing interpretation of quantum mechanics seems to require that the universe systematically violate the identity principle of logic, when such an account is totally unnecessary for explaining what we observe? Why must we rely on logically absurd "mixed states" - states which simultaneously have many values - when we can simply describe such states as having many potential values, and put off ascribing it a "definite" or actualized existence until it has actually been implicated in observation? No law of mutual displacement is in effect among potential states (only actual states).

Well I'm not a quantum physicist but I thought the manifestation of superposition is seen in the double slit experiment.

Observation constantly collapses the wave functions of the light particles producing the pattern. It's not like the pattern is the result of one light particle in all of those places at once. In other words, absence any observation, the light particle behaves like a wave with many different potential trajectories, and once it is observed its actual path is retroactively determined.

No but the interference pattern is sometimes explained as the result of particle superpositions interfering with each other. And because this experiment produces an interference pattern even when one particle is shot at a time over time, the inference is that the particle is interfering with itself. I say particle but the same is true if you consider the light to be a wave of energy as well.

http://web.mit.edu...

I thought superposition was actual first alluded to by August Kekul", a German chemist in 1872, who suggested in the structure of Benzene where oscillating single and double bonds. Later refined by Linus Pauling in 1928 now known as "resonance". ((Who said Science doesn't change it's words or meaning of them?))

Primer on Resonance
http://arxiv.org...
dylancatlow
Posts: 12,245
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3/9/2015 5:51:52 PM
Posted: 1 year ago
At 3/9/2015 5:23:49 PM, Mhykiel wrote:
At 3/9/2015 4:48:02 PM, dylancatlow wrote:
At 3/9/2015 4:36:36 PM, Mhykiel wrote:
At 3/9/2015 11:19:53 AM, dylancatlow wrote:
Can someone explain why the prevailing interpretation of quantum mechanics seems to require that the universe systematically violate the identity principle of logic, when such an account is totally unnecessary for explaining what we observe? Why must we rely on logically absurd "mixed states" - states which simultaneously have many values - when we can simply describe such states as having many potential values, and put off ascribing it a "definite" or actualized existence until it has actually been implicated in observation? No law of mutual displacement is in effect among potential states (only actual states).

Well I'm not a quantum physicist but I thought the manifestation of superposition is seen in the double slit experiment.

Observation constantly collapses the wave functions of the light particles producing the pattern. It's not like the pattern is the result of one light particle in all of those places at once. In other words, absence any observation, the light particle behaves like a wave with many different potential trajectories, and once it is observed its actual path is retroactively determined.

No but the interference pattern is sometimes explained as the result of particle superpositions interfering with each other. And because this experiment produces an interference pattern even when one particle is shot at a time over time, the inference is that the particle is interfering with itself. I say particle but the same is true if you consider the light to be a wave of energy as well.

It's not actually inferring with itself. Rather, the final result is determined within the range of values associated with the wave functions as if they had engaged. Since each wave function is limited by the previous one, the final position of the light particle must "intersect" with a continuous chain of wave functions, which is why it produces the pattern.


http://web.mit.edu...

I thought superposition was actual first alluded to by August Kekul", a German chemist in 1872, who suggested in the structure of Benzene where oscillating single and double bonds. Later refined by Linus Pauling in 1928 now known as "resonance". ((Who said Science doesn't change it's words or meaning of them?))

Primer on Resonance
http://arxiv.org...
Mhykiel
Posts: 5,987
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3/9/2015 6:37:03 PM
Posted: 1 year ago
At 3/9/2015 5:51:52 PM, dylancatlow wrote:
At 3/9/2015 5:23:49 PM, Mhykiel wrote:
At 3/9/2015 4:48:02 PM, dylancatlow wrote:
At 3/9/2015 4:36:36 PM, Mhykiel wrote:
At 3/9/2015 11:19:53 AM, dylancatlow wrote:
Can someone explain why the prevailing interpretation of quantum mechanics seems to require that the universe systematically violate the identity principle of logic, when such an account is totally unnecessary for explaining what we observe? Why must we rely on logically absurd "mixed states" - states which simultaneously have many values - when we can simply describe such states as having many potential values, and put off ascribing it a "definite" or actualized existence until it has actually been implicated in observation? No law of mutual displacement is in effect among potential states (only actual states).

Well I'm not a quantum physicist but I thought the manifestation of superposition is seen in the double slit experiment.

Observation constantly collapses the wave functions of the light particles producing the pattern. It's not like the pattern is the result of one light particle in all of those places at once. In other words, absence any observation, the light particle behaves like a wave with many different potential trajectories, and once it is observed its actual path is retroactively determined.

No but the interference pattern is sometimes explained as the result of particle superpositions interfering with each other. And because this experiment produces an interference pattern even when one particle is shot at a time over time, the inference is that the particle is interfering with itself. I say particle but the same is true if you consider the light to be a wave of energy as well.

It's not actually inferring with itself. Rather, the final result is determined within the range of values associated with the wave functions as if they had engaged. Since each wave function is limited by the previous one, the final position of the light particle must "intersect" with a continuous chain of wave functions, which is why it produces the pattern.


http://web.mit.edu...

I thought superposition was actual first alluded to by August Kekul", a German chemist in 1872, who suggested in the structure of Benzene where oscillating single and double bonds. Later refined by Linus Pauling in 1928 now known as "resonance". ((Who said Science doesn't change it's words or meaning of them?))

Primer on Resonance
http://arxiv.org...

Well if you aren't going to read my links.

This guy Wineland and his team at the National Institute for Science and Technology won a Nobel in Physics 2012 for observing superposition in Beryllium.

Nobel Press Release.
http://www.nobelprize.org...

NIST Release
http://physics.nist.gov...
"Next, additional pulses of laser radiation were delicately applied, producing a tiny force in a manner that pushed one way on the ``up' electron state, and the opposite way on the ``down' state. This force, in effect, gently shoved the two states apart without collapsing them to a single entity, so that the states that were superimposed on each other in the original ion became two physically separated states. The separation was more than 80 nanometers, or 11 times the size of the original ion."

And in Quantum computing superposition is used to solve equations simultaneously due to the fact that the interacting particles are in multiple states at one time.
RuvDraba
Posts: 6,033
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3/9/2015 7:02:13 PM
Posted: 1 year ago
At 3/9/2015 11:19:53 AM, dylancatlow wrote:
Can someone explain why the prevailing interpretation of quantum mechanics seems to require that the universe systematically violate the identity principle of logic, when such an account is totally unnecessary for explaining what we observe?

That sounds a bit more like string theory, Dylan, though I agree that quantum 'entanglements' do seem a bit spooky.

Our notions of identity themselves though, are a little circular. We hold that one object cannot be in two places at the same time -- which postulate simultaneously defines space, time and identity for us: space being a way of separating identity in common time (e.g. an alibi); time being a way of preserving identity through changes of space (e.g. a GPS tracker); and identity being a way of using space to track time (e.g. a swinging pendulum.)

When we see that kind of circularity it often suggests there are other, equally legitimate and less circular accounts. Like you, Dylan, I'm not struck by the elegance of the alternatives I've seen, but that doesn't mean we must forever remain with the current account.
dylancatlow
Posts: 12,245
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3/9/2015 8:15:02 PM
Posted: 1 year ago
At 3/9/2015 6:37:03 PM, Mhykiel wrote:
At 3/9/2015 5:51:52 PM, dylancatlow wrote:
At 3/9/2015 5:23:49 PM, Mhykiel wrote:
At 3/9/2015 4:48:02 PM, dylancatlow wrote:
At 3/9/2015 4:36:36 PM, Mhykiel wrote:
At 3/9/2015 11:19:53 AM, dylancatlow wrote:
Can someone explain why the prevailing interpretation of quantum mechanics seems to require that the universe systematically violate the identity principle of logic, when such an account is totally unnecessary for explaining what we observe? Why must we rely on logically absurd "mixed states" - states which simultaneously have many values - when we can simply describe such states as having many potential values, and put off ascribing it a "definite" or actualized existence until it has actually been implicated in observation? No law of mutual displacement is in effect among potential states (only actual states).

Well I'm not a quantum physicist but I thought the manifestation of superposition is seen in the double slit experiment.

Observation constantly collapses the wave functions of the light particles producing the pattern. It's not like the pattern is the result of one light particle in all of those places at once. In other words, absence any observation, the light particle behaves like a wave with many different potential trajectories, and once it is observed its actual path is retroactively determined.

No but the interference pattern is sometimes explained as the result of particle superpositions interfering with each other. And because this experiment produces an interference pattern even when one particle is shot at a time over time, the inference is that the particle is interfering with itself. I say particle but the same is true if you consider the light to be a wave of energy as well.

It's not actually inferring with itself. Rather, the final result is determined within the range of values associated with the wave functions as if they had engaged. Since each wave function is limited by the previous one, the final position of the light particle must "intersect" with a continuous chain of wave functions, which is why it produces the pattern.


http://web.mit.edu...

I thought superposition was actual first alluded to by August Kekul", a German chemist in 1872, who suggested in the structure of Benzene where oscillating single and double bonds. Later refined by Linus Pauling in 1928 now known as "resonance". ((Who said Science doesn't change it's words or meaning of them?))

Primer on Resonance
http://arxiv.org...

Well if you aren't going to read my links.

This guy Wineland and his team at the National Institute for Science and Technology won a Nobel in Physics 2012 for observing superposition in Beryllium.

Nobel Press Release.
http://www.nobelprize.org...

NIST Release
http://physics.nist.gov...
"Next, additional pulses of laser radiation were delicately applied, producing a tiny force in a manner that pushed one way on the ``up' electron state, and the opposite way on the ``down' state. This force, in effect, gently shoved the two states apart without collapsing them to a single entity, so that the states that were superimposed on each other in the original ion became two physically separated states. The separation was more than 80 nanometers, or 11 times the size of the original ion."

And in Quantum computing superposition is used to solve equations simultaneously due to the fact that the interacting particles are in multiple states at one time.

Quantum computing does not actually require that particles be in multiple places at once, just that those potential positions - and the corresponding effect - be calculated by nature.
chui
Posts: 507
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3/10/2015 10:54:26 AM
Posted: 1 year ago
At 3/9/2015 11:19:53 AM, dylancatlow wrote:
Can someone explain why the prevailing interpretation of quantum mechanics seems to require that the universe systematically violate the identity principle of logic, when such an account is totally unnecessary for explaining what we observe? Why must we rely on logically absurd "mixed states" - states which simultaneously have many values - when we can simply describe such states as having many potential values, and put off ascribing it a "definite" or actualized existence until it has actually been implicated in observation? No law of mutual displacement is in effect among potential states (only actual states).

The basic reason is that it works. The mathematical description of a particle is a superposition of waves of varying wavelength, each wavelength representing a different value of properties such as energy and momentum (normally called a wave packet). These wave superposition solutions come from solving the Schrodinger equation for a given potential. They appear to describe nature very accurately.

The superposition description is in all interpretations of quantum physics because the mathematics is identical. Bohm's hidden variable theory still uses superposition but assumes that quantum physics is an incomplete description of reality. Bell's test experiments have shown that hidden variable theories are probably wrong, although a few loopholes still exist that might allow a Bohm type theory to work.

Experiments such as the double slit can only be explained in terms of wave superposition and the experiment gives the same result if we send only one particle at a time through the slits. What can be causing superposition if only a single particle is in the apparatus?

Quantum physics is a complete set of ideas and equations which works very well in many applications and gives good agreement to classical physics at the boundary between quantum and classical physics. It has been shown to be consistent with special relativity and progress is being made to make it work with general relativity. Quantum physics seems to be very successful so is probably right.

The inability of science to explain in words what quantum physics is about stems from the fact that language is not designed to explain quantum physics. Mathematics gives a clearer explanation of quantum physics but not many people 'speak' maths. The human mind finds it hard to accept what the mathematics is describing, but the human mind was not designed to understand quantum physics, rather it evolved to help us survive life on the African savanna.
debate_power
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3/11/2015 3:58:16 PM
Posted: 1 year ago
At 3/9/2015 11:19:53 AM, dylancatlow wrote:
Can someone explain why the prevailing interpretation of quantum mechanics seems to require that the universe systematically violate the identity principle of logic, when such an account is totally unnecessary for explaining what we observe? Why must we rely on logically absurd "mixed states" - states which simultaneously have many values - when we can simply describe such states as having many potential values, and put off ascribing it a "definite" or actualized existence until it has actually been implicated in observation? No law of mutual displacement is in effect among potential states (only actual states).

Well, that's what Schroedinger tried to explain with his cat scenario. I can't really explain why the prevailing conception would seem to be that way. I certainly hope it is not.
You can call me Mark if you like.