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> Actually, all physicists admit that parallel worlds exist on the microscopic scale No they don't. The many worlds theory is a very tentative suggestion. And

> Actually, all physicists admit that parallel worlds exist on the microscopic scale No they don't. The many worlds theory is a very tentative suggestion. And even if that was a professional opinion, does it have any consequences for the theory or is it an after thought?

Viliam1234 8y ago
Many world theory is about what happens on macroscopic scale. Specifically, it says: "The world on the macro scale is still governed by the same laws of physics as on the micro scale, duh. There are no extra laws of physics (such as collapse) which would start to apply only when the number of particles involved in the experiment exceeds some unspecified threshold." And yes, there are people who agree with this, and there are people who disagree with this, even among the experts. But on microscopic scale, it is a general consensus that in the double-slit experiment the particle somehow goes simultaneously through both slits, i.e. that two different realities (different only in trajectory of a single particle) somehow got into superposition. The disagreement is only about "what will happen with this superposition, when more and more particles enter the game". Some theories say "at some moment, the superposition of multiple realities will somehow collapse, and only one reality will emerge victorious". Some theories say "the additional particles will also get entangled with the particles that are already there". The former predict that the observer will only see one outcome, because when the human brain is entangled, the collapse already happened and there is now only one reality. The latter predict that each observer will only see one outcome, because each outcome gets entangled with the version of observer observing that specific outcome. Both theories agree that at the end the observer will report to only see one outcome. I guess the experimental consequence of the no-collapse interpretations of quantum physics would be that quantum computers of arbitrary size will be possible. If you instead believe that an interaction with e.g. 1000 particles will collapse, that would put a limit on number of possible qubits. But of course, if someone would falsify that theory by building a larger quantum computer, nothing prevents you from saying "did I say 1000 particles? I actually meant 10000 particles!" and have the theory survive yet another day. Of course, you can also come up with a theory saying "the superposition of too many particles will collapse unless it happens to be inside of a quantum computer"; etc. But at that moment it should be obvious you are just making excuses. Now let me ask you in return: Is there any specific prediction of when exactly does the collapse happen? Was it ever experimentally observed to happen?
- posterboy 8y ago
  > general concensus This is a weasel word (as per e.g. Wikipedia:WEASEL). You need to accompany that with a quote at the very least for "two different realities (...) somehow got into superposition". And even then I wouldn't buy it if the quote was from popular science or by-the-way opinions. Simply because that's a contradiction. The two slit open phase is described in a wave model and the other phase in a particle. model. But neither is correct at the same time. That's been good enough for me so far. You might as well say both models were correct and somehow get into super position. But how is somehow important. I have never calculated a wave collapse or even began to understand the PSI operator. I don't think it would lead me anywhere unless taking the slit, or rather the barrier into the equation. But no, you skip ahead and entangle the whole human brain. Excuse me: What?
- posterboy 8y ago
  > Now let me ask you in return: Is there any specific prediction of when exactly does the collapse happen? Was it ever experimentally observed to happen? I had missed that question. I don't know, to be honest. I hadn't even mentioned it. The Kopenhagen interpretation is famous, but I guess inconsequential the same way that entanglement cannot violate the speed limit for information transmission.

Viliam1234 8y ago

Many world theory is about what happens on macroscopic scale. Specifically, it says: "The world on the macro scale is still governed by the same laws of physics as on the micro scale, duh. There are no extra laws of physics (such as collapse) which would start to apply only when the number of particles involved in the experiment exceeds some unspecified threshold." And yes, there are people who agree with this, and there are people who disagree with this, even among the experts. But on microscopic scale, it is a general consensus that in the double-slit experiment the particle somehow goes simultaneously through both slits, i.e. that two different realities (different only in trajectory of a single particle) somehow got into superposition. The disagreement is only about "what will happen with this superposition, when more and more particles enter the game". Some theories say "at some moment, the superposition of multiple realities will somehow collapse, and only one reality will emerge victorious". Some theories say "the additional particles will also get entangled with the particles that are already there". The former predict that the observer will only see one outcome, because when the human brain is entangled, the collapse already happened and there is now only one reality. The latter predict that each observer will only see one outcome, because each outcome gets entangled with the version of observer observing that specific outcome. Both theories agree that at the end the observer will report to only see one outcome. I guess the experimental consequence of the no-collapse interpretations of quantum physics would be that quantum computers of arbitrary size will be possible. If you instead believe that an interaction with e.g. 1000 particles will collapse, that would put a limit on number of possible qubits. But of course, if someone would falsify that theory by building a larger quantum computer, nothing prevents you from saying "did I say 1000 particles? I actually meant 10000 particles!" and have the theory survive yet another day. Of course, you can also come up with a theory saying "the superposition of too many particles will collapse unless it happens to be inside of a quantum computer"; etc. But at that moment it should be obvious you are just making excuses. Now let me ask you in return: Is there any specific prediction of when exactly does the collapse happen? Was it ever experimentally observed to happen?

posterboy 8y ago
> general concensus This is a weasel word (as per e.g. Wikipedia:WEASEL). You need to accompany that with a quote at the very least for "two different realities (...) somehow got into superposition". And even then I wouldn't buy it if the quote was from popular science or by-the-way opinions. Simply because that's a contradiction. The two slit open phase is described in a wave model and the other phase in a particle. model. But neither is correct at the same time. That's been good enough for me so far. You might as well say both models were correct and somehow get into super position. But how is somehow important. I have never calculated a wave collapse or even began to understand the PSI operator. I don't think it would lead me anywhere unless taking the slit, or rather the barrier into the equation. But no, you skip ahead and entangle the whole human brain. Excuse me: What?
posterboy 8y ago
> Now let me ask you in return: Is there any specific prediction of when exactly does the collapse happen? Was it ever experimentally observed to happen? I had missed that question. I don't know, to be honest. I hadn't even mentioned it. The Kopenhagen interpretation is famous, but I guess inconsequential the same way that entanglement cannot violate the speed limit for information transmission.