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Philip Van Hoof
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As an engineer I was interested in the setup of the experiment described in '1-6 Watching the electrons' of Feynman's recently published lectures.
I understand that a method that is used to detect whether the 'particle' passes through hole 1 or 2 is to use a wave of a wavelength that is either longer than or shorter than the distance between the holes.
While trying to map this experiment to the real world I imagined this as making a wave in an shallow pool to see it get disturbed by a person who's slowly walking over the bottom of the pool (the 'particle') and then at the sides of the pool measuring the arriving waves to locate the walking person and to know about his momentum. To complete the mapping to a pool it has two entrances to it and people get asked to walk in a straight line over the bottom while not caring about external influences (our waves might influence them, we don't know).
The chapter explains that a 'terrible thing' happens depending solely on the wavelength of our waves being shorter or longer than the distance between holes 1 and 2 (doing a measurement with a definable answer or not doing one that will yield a definable answer).
A 'disturbance' is caused when it is shorter (it makes the walker stick to his earlier decision which hole he used to enter the pool). When it is longer we see a interference pattern: the walker acts like a wave coming out of the pool's gates, even interfering with future walkers. He's no longer a particle but a wave as for all we know he acts like one. I hope I didn't mix the two results up :-)
In '1–8 The uncertainty principle' an alternative method is discussed allowing the entrace holes to experience a (measurable) recoil up or down based on which hole the 'particle' chose. I'm not convinced that the recoil-movement of the wall has no influence on the 'particle' and its final path.
I wonder if ever experiments have been done where the direction of the wave to detect the 'particle' doesn't come from left or right of the holes, nor from in the middle of the holes where it's left for 2 and right for 1 (like described in Fig 1-4) but from above and/or below 1 and 2.
I also wonder if ever experiments have been done where the time between two 'particles' is very long (does this still create interference).
ps. I realize this is related to this thread, I'll read all of it later: https://www.physicsforums.com/threads/double-slit-experiment-and-watching-the-electrons.727431/
I understand that a method that is used to detect whether the 'particle' passes through hole 1 or 2 is to use a wave of a wavelength that is either longer than or shorter than the distance between the holes.
While trying to map this experiment to the real world I imagined this as making a wave in an shallow pool to see it get disturbed by a person who's slowly walking over the bottom of the pool (the 'particle') and then at the sides of the pool measuring the arriving waves to locate the walking person and to know about his momentum. To complete the mapping to a pool it has two entrances to it and people get asked to walk in a straight line over the bottom while not caring about external influences (our waves might influence them, we don't know).
The chapter explains that a 'terrible thing' happens depending solely on the wavelength of our waves being shorter or longer than the distance between holes 1 and 2 (doing a measurement with a definable answer or not doing one that will yield a definable answer).
A 'disturbance' is caused when it is shorter (it makes the walker stick to his earlier decision which hole he used to enter the pool). When it is longer we see a interference pattern: the walker acts like a wave coming out of the pool's gates, even interfering with future walkers. He's no longer a particle but a wave as for all we know he acts like one. I hope I didn't mix the two results up :-)
In '1–8 The uncertainty principle' an alternative method is discussed allowing the entrace holes to experience a (measurable) recoil up or down based on which hole the 'particle' chose. I'm not convinced that the recoil-movement of the wall has no influence on the 'particle' and its final path.
I wonder if ever experiments have been done where the direction of the wave to detect the 'particle' doesn't come from left or right of the holes, nor from in the middle of the holes where it's left for 2 and right for 1 (like described in Fig 1-4) but from above and/or below 1 and 2.
I also wonder if ever experiments have been done where the time between two 'particles' is very long (does this still create interference).
ps. I realize this is related to this thread, I'll read all of it later: https://www.physicsforums.com/threads/double-slit-experiment-and-watching-the-electrons.727431/