5 ms·
They have not been explicitly looked at, but they have been observed in the QM sense. That’s because decoherence has spread those records to conscious observers
by akvadrako 6y ago
They have not been explicitly looked at, but they have been observed in the QM sense. That’s because decoherence has spread those records to conscious observers.
If the results had been kept completely isolated from all people, you could still say a measurement hasn’t occurred.
- trenchgun 6y agoWhy from all people? What if there is a person in an lab which is isolated from the rest of the people?
- kgwgk 6y agoWigner’s friend?
- akvadrako 6y agoThen he will certainly be able to say a measurement happened. That’s something only conscious beings can do.
- rbanffy 6y agoBut then isn't Wigner's friend also in a superposition until Wigner talks to them?
- akvadrako 6y agoTraditional QM does not allow Wigner’s friend to be in superposition.
- rbanffy 6y agoUntil he talks to them, how can Wigner tell? ;-)
- akvadrako 6y agoWigner can’t tell, but the friend knows. If he thought he was in a superposition he would believe in many worlds.
- rbanffy 6y agoBut shouldn't every friend in every possible state observe a single state that's consistent with their own internal state? The friend only exists in many worlds from Winger's perspective, and only as long as their state has no causal effect on Wigner's own state.
- ithkuil 6y agoWhat's wrong with many worlds?
- akvadrako 6y agoIt’s not what this thread is about.
- ithkuil 6y agoI guess I got confused at "If he thought he was in a superposition he would believe in many worlds." Do you mean "he can either think he can be in superposition or he cannot be, if he thinks he can be then he would believe in many worlds, which is incompatible with 'traditional' QM, which thus implies 'Traditional QM does not allow Wigner’s friend to be in superposition.'" ? I don't think the Traditional QM ever explicitly disallowed a person to be in superposition; being in superposition it's just not something "decent people" do, I suppose. Thus we needed to find other ways to come to terms with what we observe. But the math is the same. The rest is only metaphors that help us reconcile what we observe with how we feel inside. Thus, many worlds is not antithetic to traditional QM.
- akvadrako 6y agoDo you think that many quantum physicists during the 21st century accepted the possibility of living in a splitting multiverse? I don't think that's historically accurate. If you read about how Everett's ideas were treated it's pretty clear traditional QM is antithetic to many worlds.
- millstone 6y agoThat's just not what traditional QM says. Traditional QM separates quantum systems (microscopic) from measurements devices (macroscopic). A measurement occurs when the measurement device interacts with the quantum system. You do QM by predicting the results of these measurements. Consciousness does not enter into it.
- BadThink6655321 6y agoUntil you get information from the measurement, it didn’t happen.
- rbanffy 6y agoCan it be considered as until it causally affects something else (the observer), its state is not defined? Isn't it a causal relation that collapses the superposition?
- TheOtherHobbes 6y agoSo why doesn't a measurement and/or decoherence occur when double slits or a half-silvered mirror interact with a passing particle? Are they not macroscopic objects which interact with the quantum information? Perhaps it's only a "measurement" if the (alleged) particle has nowhere else to go after the interaction. But how does the (alleged) particle know which macroscopic interactions are terminal and should be counted as "measurements" and which are part of the rest of the experiment? There is no answer to this in QM. You can calculate the probabilities and you will get predictable answers, but there are still >20 interpretations of what is really happening, and they all disagree with each other in important ways.