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Author Topic: What is weak measurements, and, why do we expect it to be equivalent to HUP?  (Read 7775 times)

Offline Mr. Data

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Yeah, the most interesting things (to me) isn't the forefront of physics, rather the ideas we build that forefront on. There's only so much time and we need to get it right before the measure runs out. QM today is rather incredible, as we test its limits, and find ways to circumvent them.

One of the biggest questions to me is just how I should see a weak measurement, because that reflects on how you define the world. You could argue that before flipping a coin it has a very real existence, although you from your defined intention, now might state that it is in a 'superposition' of states. That wouldn't be right though, the superposition only come to exist in the 'flipping' of it. And that's one simple definition of it, making it into some sort of 'predefined statistics'. But I don't know if that is what HUP speaks about? To me HUP is about a groundstate of uncertainty with the opposite being 'histories'(as weak measurements are). A symmetry of sorts again, isn't it?

You might want to argue that this is the way to define reality, using weak measurements, as they are 'statistically significant' meaning that from that experiment you now can draw conclusions valid for all other experiments done inside SpaceTime. But in some weird way I find that boring :) I want reality to fill me with wonder, not dreariness and statistics.

Also it doesn't push the borders, it just give a statistic significance to what we already knew without those 'statistics'. That doesn't mean it isn't one of the best tools we have to define a reality, but just as statistics can define populations, it fails to define the individual.

I don't know if there is any true physical representation of a coupling between two systems, only that the act of observation disturbs the wave function, and that it can lead to the collapse of the observed system. There are a few theories in physics which likes to deal with the observer-observed dependancy models. In a sense, these kind of models only exist in physics, because they are in themselves principles suggesting that attributes of things do not exist at the subatomic level unless there is something there to observe it. Obviously that kind of world though, is often misunderstood that on the levels of the macroscopic world, trees don't fall unless someone is there to hear them fall, or watch them fall.
 

Offline Mr. Data

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But I carefully said ''can lead to a collapse...''

Not all observations lead to collapsed states, some lead to quantum entangled states, such as a positronium, a particle which consists of a tightly bound state of an electron and a positron. This is Hardy's Paradox.
 

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