Physicists at ANU Experimentally Conclude (again) That Physical Reality Exists Only When Observed

#1
http://phys.org/news/2015-05-quantu...e=menu&utm_medium=link&utm_campaign=item-menu

Experiment confirms quantum theory weirdness


The bizarre nature of reality as laid out by quantum theory has survived another test, with scientists performing a famous experiment and proving that reality does not exist until it is measured.


Physicists at The Australian National University (ANU) have conducted John Wheeler's delayed-choice thought experiment, which involves a moving object that is given the choice to act like a particle or a wave. Wheeler's experiment then asks - at which point does the object decide?

Common sense says the object is either wave-like or particle-like, independent of how we measure it. But quantum physics predicts that whether you observe wave like behavior (interference) or particle behavior (no interference) depends only on how it is actually measured at the end of its journey. This is exactly what the ANU team found.

"It proves that measurement is everything. At the quantum level, reality does not exist if you are not looking at it," said Associate Professor Andrew Truscott from the ANU Research School of Physics and Engineering.

Despite the apparent weirdness, the results confirm the validity of quantum theory, which governs the world of the very small, and has enabled the development of many technologies such as LEDs, lasers and computer chips.

The ANU team not only succeeded in building the experiment, which seemed nearly impossible when it was proposed in 1978, but reversed Wheeler's original concept of light beams being bounced by mirrors, and instead used atoms scattered by laser light.

"Quantum physics' predictions about interference seem odd enough when applied to light, which seems more like a wave, but to have done the experiment with atoms, which are complicated things that have mass and interact with electric fields and so on, adds to the weirdness," said Roman Khakimov, PhD student at the Research School of Physics and Engineering.

Professor Truscott's team first trapped a collection of helium atoms in a suspended state known as a Bose-Einstein condensate, and then ejected them until there was only a single atom left.

The single atom was then dropped through a pair of counter-propagating laser beams, which formed a grating pattern that acted as crossroads in the same way a solid grating would scatter light.

A second light grating to recombine the paths was randomly added, which led to constructive or destructive interference as if the atom had travelled both paths. When the second light grating was not added, no interference was observed as if the atom chose only one path.

However, the random number determining whether the grating was added was only generated after the atom had passed through the crossroads.

If one chooses to believe that the atom really did take a particular path or paths then one has to accept that a future measurement is affecting the atom's past, said Truscott.

"The atoms did not travel from A to B. It was only when they were measured at the end of the journey that their wave-like or particle-like behavior was brought into existence," he said.
 
#3
And now we just have to figure out what it means to observe.

~~ Paul
Yes, couldn't agree more.

I don't understand quantum physics, I once attempted to learn higher physics diligently but failed, I need to learn to earn my living most importantly.

But, I fathom, is it possible that there should always be a global observer, to accommodate a hypothetical existence without a "concrete" observer observing it.

In other words, is it possible that there is somehow a super observer who always observes everything thus sustains their existence.

For example, that famous experiment of Xuedinge's Cat, although there is no "people"(researcher) to observe its result, but there is always a super observer to know the result, this super observer just doesn't care about telling anyone else?

Sorry English is not my mother tongue :D
 
#4
Yes, couldn't agree more.

I don't understand quantum physics, I once attempted to learn higher physics diligently but failed, I need to learn to earn my living most importantly.

But, I fathom, is it possible that there should always be a global observer, to accommodate a hypothetical existence without a "concrete" observer observing it.

In other words, is it possible that there is somehow a super observer who always observes everything thus sustains their existence.

For example, that famous experiment of Xuedinge's Cat, although there is no "people"(researcher) to observe its result, but there is always a super observer to know the result, this super observer just doesn't care about telling anyone else?

Sorry English is not my mother tongue :D
The term super observer is actually used in the early papers of Wheeler. He thought so.
 
#5
is it possible that there should always be a global observer, to accommodate a hypothetical existence without a "concrete" observer observing it.
I'd say it's possible but not actual. That's not how this set of physical realities is set up.

Instead of getting into the usual "how do you know?" tussle, I'll stick to the data of some physics experiments. What has been recorded is that every instance of measurement/observation changes what is measured/observed - if "global observation" were the case that would not be so. The physical reality you encounter is yours and yours alone. And to avoid another tussle - yes the standard is that there are similarities in what each M/O generates so certainly I can go to St Pauls in Rome and it will exist much the same way as it does for most other visitors. But there will be differences for each individual. In fact there will be differences for the same individual from moment to moment. But on a scale that most will rarely ever notice.
 
#6
And now we just have to figure out what it means to observe.

~~ Paul
To observe: is to have mutual information, as an agent, about the thing, event or processes being observed. I like stuff we can measure.

I do not find the results of this physically manifested variation of Wheeler's "delayed choice" thought experiment being unusual or strange. Why people, who have escaped materialism, still think when you "export" information from a physical system, that the system shouldn't be changed. It is flat-earth thinking in an age of informational realism.

Exporting the information to a state of mutual information, via the measurement, changes the informational structure of the real world environment. Patterns of interference change with this change in underlying structure. (of course this is outta-the-box thinking)
 

Paul C. Anagnostopoulos

Nap, interrupted.
Member
#11
To observe: is to have mutual information, as an agent, about the thing, event or processes being observed. I like stuff we can measure.
It doesn't matter what definition you quote or invent. The question is: What is required to act as the "observer" in the quantum mechanical sense? Most physicists say that consciousness is not required, although some say it is. We shall see.

~~ Paul
 
#12
The question is: What is required to act as the "observer" in the quantum mechanical sense?
~~ Paul
The act required for an observer at any scale, is to have a quantity of mutual information whose knowledge can change real world probability for future outcomes. In my humble opinion, quantum experiments prove that if both position and momentum are known about a physical particle; its stochastic interference pattern is structurally different. i.e. it's information is structured differently because the particle's future probability for location and energy is different.
 

Paul C. Anagnostopoulos

Nap, interrupted.
Member
#13
The act required for an observer at any scale, is to have a quantity of mutual information whose knowledge can change real world probability for future outcomes. In my humble opinion, quantum experiments prove that if both position and momentum are known about a physical particle; its stochastic interference pattern is structurally different. i.e. it's information is structured differently because the particle's future probability for location and energy is different.
Sorry, I don't know what you mean. And we cannot know both the position and momentum of a particle.

~~ Paul
 
#14
Most physicists say that consciousness is not required, although some say it is. We shall see.
l
<sigh> It's important to know that what those physicist mean by "consciousness" is not what people like myself (and a few others here) mean by the term. By consciousness we mean the non-physical source to all that exists. I get that you don't know or, in your terms "believe" there is such, but even in arguing that viewpoint it's important to be clear on what's being discussed. Otherwise the discussion keeps getting stuck on explaining what is meant. In the meaning I've explained a rock is as much an expression of consciousness as a human being. The entire physical framework is one expression of consciousness. Surely when I've stated that before you didn't think I meant an expression of human awareness?
 

Paul C. Anagnostopoulos

Nap, interrupted.
Member
#15
<sigh> It's important to know that what those physicist mean by "consciousness" is not what people like myself (and a few others here) mean by the term. By consciousness we mean the non-physical source to all that exists. I get that you don't know or, in your terms "believe" there is such, but even in arguing that viewpoint it's important to be clear on what's being discussed. Otherwise the discussion keeps getting stuck on explaining what is meant. In the meaning I've explained a rock is as much an expression of consciousness as a human being. The entire physical framework is one expression of consciousness. Surely when I've stated that before you didn't think I meant an expression of human awareness?
If we assume that the fundamental existent is consciousness-like, then I certainly can't argue that consciousness is required for collapse. It's also required for everything else, by definition. So then the question becomes:

Does collapse require individual sentient consciousness, or only universal consciousness?

~~ Paul
 
#16
Does collapse require individual sentient consciousness, or only universal consciousness?

~~ Paul
I'm getting nervous. It's looking like, agree or not, we may actually have a discourse on the actual issue at hand rather than one that is on me explaining the basics of what I've posted. :)

I'll alter your question to Does collapse require human awareness?

So it would seem that that is something that science-AWKI could explore. However I'd think it would require advance pseudo-AI to pull off. Short of that human awareness would be involved at some point. Other experiments have resulted in those involved concluding that even observing "afterwards" affects the physical state that is generated
 

Paul C. Anagnostopoulos

Nap, interrupted.
Member
#17
I'm getting nervous. It's looking like, agree or not, we may actually have a discourse on the actual issue at hand rather than one that is on me explaining the basics of what I've posted. :)
Uh oh.

I'll alter your question to Does collapse require human awareness?

Okay.

So it would seem that that is something that science-AWKI could explore. However I'd think it would require advance pseudo-AI to pull off. Short of that human awareness would be involved at some point. Other experiments have resulted in those involved concluding that even observing "afterwards" affects the physical state that is generated
But if we say that there is no collapse without human awareness, then we have to assume that the entire universe was in a superposed state until the first human. Or perhaps the first ape. Or bird? Exactly how much awareness is required to collapse? Did the first aware-organism collapse the entire universe, or just a local bit? When I go to sleep, does my little corner of the universe go into superposition until I awake?

It's a bit too egotistic for my taste.

~~ Paul
 
#18
But if we say that there is no collapse without human awareness, then we have to assume that the entire universe was in a superposed state until the first human. Or perhaps the first ape. Or bird? Exactly how much awareness is required to collapse? Did the first aware-organism collapse the entire universe, or just a local bit? When I go to sleep, does my little corner of the universe go into superposition until I awake?
I'm going to keep being scientific about this discourse so we'll toss the "too egotistic." Whether you or like it or not is irrelevant.

Next you are making assumptions. Your reality is your observation of it. In one sense, when you say read about the universe all that is "real" is that you are reading about the universe. In another sense thinking of something is part of human awareness so that in itself may play a part in collapse.

The other valid (IMO) question you've raised is about when you go to sleep. Of course that's a whole complicated think and we'd have to discourse about all the various actions that are possible in that state.

The upshot is that since your assessing is being done by your standard human awareness, all of it is part of your own observation. So back we go to that pseudo-AI
 

Paul C. Anagnostopoulos

Nap, interrupted.
Member
#19
The upshot is that since your assessing is being done by your standard human awareness, all of it is part of your own observation. So back we go to that pseudo-AI
I agree that it's possible that it's all superposed until some sort of aware entity observes some part of it. However, if so, I think we have a lot of explaining to do. For example, we have to deal with Wigner's friend:

http://en.wikipedia.org/wiki/Wigner's_friend

We also have to decide exactly what sort/how much awareness is required. Then we wonder why there is a special case at that point.

~~ Paul
 
#20
Sorry, I don't know what you mean. And we cannot know both the position and momentum of a particle.

~~ Paul
Paul,
You have left out the word "simultaneously" in your response and it is a critical aspect of the concept.

I am no expert in this area, however in sequential measurements, I believe enough mutual information can be gained to obtain a good idea of the state of a particle. Remember that mutual information can be collected, in an historical account. A physical measurement (and hence, physical information) is in the "here and now". An accounting of a SoA (state of affairs) allows the compounding of information. The immediate past and future -- speak to the state of affairs.

I am open to correction in this matter and encourage better knowledge to set me aright.
 
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