Observation & measurement
@skipper-wJtaxo
•
Oct 20, 2024
Oct 20, 2024
945
I've brought these subjects up at other forums, and I have to say there appears to be a fairly wide set of viewpoints about either.
In QM. observation and measurement are definitely the same thing. Here, the paradigm is POVM, or "positive operator valued measurement". The operator is both the "momentum" a quantum state has from a perturbation in the system, and an "operator" human who applies the external field so states evolve.
I recall a discussion about the difference between a science such as astronomy, which is "observational"; and what some argued was what astronomy excludes: experimentation.
This is a claim I just can't agree with, if astronomy was only about passive observation, why bother with telescopes? Can people who believe they can't experiment with a telescope (the argument in support of the "only observe" theory is that you can't alter the subject, only look at it) only buy them and leave them in the store?
That would be the logical thing to do if you can't "experiment" with observations, by locating a telescope, pointing it at something - how do you know where to look, or why would you bother if you can only see the same old stuff, every time?
Obviously, people with telescopes do experiment with them. Otherwise, why is there a science of telescopy and a history of the development of astronomy and telescopes? Why are we experimenting with new kinds of astronomy? Why didn't Newton use radio dishes, why are we using them today, instead of the telescope Newton used - since the work had been done, there should be no need to try to build a better technology (like we have) since, all another 'scope can do is what any other can do?
This is a misconception, obviously the Hubble is experimental; it can be pointed in different directions, it has comms equipment to relay data (observations) to human beings. If all we could do was observe, why bother pointing the Hubble in any particular direction, or bother building the equipment that lets the orientation be changed, or even bother building the comms, if it's "just observing"??
So, is astronomy connected to QM, in any way? Yep, you bet. Is looking down a telescope of any kind, positive, and operator valued measurement, even though we can't directly perturb a distant object, we certainly can perturb the observation of it (with astronomical experiments, including telescopy).
More than a few people completely disagreed with my argument. They insist you can't experiment with distant objects, so this means astronomy is "just observation" whatever that might mean.
What do you think?
In QM. observation and measurement are definitely the same thing. Here, the paradigm is POVM, or "positive operator valued measurement". The operator is both the "momentum" a quantum state has from a perturbation in the system, and an "operator" human who applies the external field so states evolve.
I recall a discussion about the difference between a science such as astronomy, which is "observational"; and what some argued was what astronomy excludes: experimentation.
This is a claim I just can't agree with, if astronomy was only about passive observation, why bother with telescopes? Can people who believe they can't experiment with a telescope (the argument in support of the "only observe" theory is that you can't alter the subject, only look at it) only buy them and leave them in the store?
That would be the logical thing to do if you can't "experiment" with observations, by locating a telescope, pointing it at something - how do you know where to look, or why would you bother if you can only see the same old stuff, every time?
Obviously, people with telescopes do experiment with them. Otherwise, why is there a science of telescopy and a history of the development of astronomy and telescopes? Why are we experimenting with new kinds of astronomy? Why didn't Newton use radio dishes, why are we using them today, instead of the telescope Newton used - since the work had been done, there should be no need to try to build a better technology (like we have) since, all another 'scope can do is what any other can do?
This is a misconception, obviously the Hubble is experimental; it can be pointed in different directions, it has comms equipment to relay data (observations) to human beings. If all we could do was observe, why bother pointing the Hubble in any particular direction, or bother building the equipment that lets the orientation be changed, or even bother building the comms, if it's "just observing"??
So, is astronomy connected to QM, in any way? Yep, you bet. Is looking down a telescope of any kind, positive, and operator valued measurement, even though we can't directly perturb a distant object, we certainly can perturb the observation of it (with astronomical experiments, including telescopy).
More than a few people completely disagreed with my argument. They insist you can't experiment with distant objects, so this means astronomy is "just observation" whatever that might mean.
What do you think?