# EPR paradox, 11.8

physical definition

~ define the microscopic events in terms of observable physical phenomena such as the change of readings of the measuring device

~ `define` unobservable events in terms of observable events

— Me@2022-01-31 08:33:01 AM

The second clue:

If in your experimental design, you have planned to activate a detector when each particle is still on its path, then this activation action itself is already part of your experimental design.

The detector and the planned action of activating it have already formed a “physical definition” that makes your experiment design to have the system being in a mixed state, instead of superposition state, since the beginning of the experiment.

Put it more accurately, since a wave function is a mathematical function, not a physical field, it does not exist in physical spacetime.

Superposition is a property for some wave functions (quantum states). So superposition is not a physical phenomenon. Instead, it is a mathematical property of some physical variables of your experimental-setup design.

In a sense, instead of existing at the time level of the experiment and the observer, a wave function exists at the meta-time level, the time level of the experiment-setup designer.

So it is meaningless to say “the experimental setup is in a superposition state (or not) in the beginning of the experiment”.

Instead, whether a system is in superposition or not (with respect to a particular variable) is an intrinsic property of your experimental setup design, which includes not just objects and devices, but also operations.

“Wave function collapse” is not a physical event that happens during the operation of the experiment. Instead, it “happens” when you replace one experiment design with another.

— Me@2022-02-16 10:45:01 AM

If the experimenter does not follow the original experiment design, such as not turning on the detector at the pre-defined time, then he is actually doing another experiment, which will have a completely different probability distribution (for any particular variable).

— Me@2022-02-14 10:35:27 AM

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An experiment-setup design is composed of not only objects and devices, but also operations. A different experiment-setup design will give a different probability distribution for any particular physical variable.

Also, a different observer will see a different probability distribution for any particular physical variable. The same observer at different times actually should be regarded as different observers.

In other words, “where and when an observer should do what during the experiment” is actually part of your experimental-setup design, defining what probability distribution (for any particular variable) you (the observer) will get.

— Me@2022-02-18 07:40:14 AM

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