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norwegian_hobby_sci
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- TL;DR
- Whats a particle in QFT?
I'm trying to create a YouTube educational science video on Quantum Field Theory and the Standard Model. I'm not a physicist (just a hobby), and would love feedback on my explanation below, and help to point out (or rewrite) parts that are scientifically inacurate or misleading. Or just point me to literature.
"But something weird happens whenever we try to measure where a particle is in these fields - whether through our senses or instruments. This weirdness is related to what quantum scientists call “the measurement problem” or “the wave function collapse”. You see, when we make a measurement and locate a particle, the strengths of the field instantly changes into that particularly outcome. The field gets a big excitation at that particular point and close to 0 elsewhere. These excitations, which in some ways define the size of a particle, can be as small as we want depending on how accurate our measurement instrument is - so the concept of a particle size in quantum physics almost doesn't make much sense. In many cases, physicists simply assume that particles have a size of a point, i.e. 0, and their calculations and observations still work out. So in fact, what we call particles are nothing more than these measured excitations in the corresponding fields.
At this point you may mistakenly be thinking that the particle (i.e. excitation) exist before we measure, but we dont know about it until after the measurement. This is called hidden-variables theory and has been called into question by several experiments. For example in the double-slit experiment we can see that the spread out wave patterns of the quantum field strength before measurement affect real-world outcomes. This wave state of the quantum field are the best explanation for how the field can interact with itself and produces wave-like interference patterns [This last paragraph has been less polished by me]."
"But something weird happens whenever we try to measure where a particle is in these fields - whether through our senses or instruments. This weirdness is related to what quantum scientists call “the measurement problem” or “the wave function collapse”. You see, when we make a measurement and locate a particle, the strengths of the field instantly changes into that particularly outcome. The field gets a big excitation at that particular point and close to 0 elsewhere. These excitations, which in some ways define the size of a particle, can be as small as we want depending on how accurate our measurement instrument is - so the concept of a particle size in quantum physics almost doesn't make much sense. In many cases, physicists simply assume that particles have a size of a point, i.e. 0, and their calculations and observations still work out. So in fact, what we call particles are nothing more than these measured excitations in the corresponding fields.
At this point you may mistakenly be thinking that the particle (i.e. excitation) exist before we measure, but we dont know about it until after the measurement. This is called hidden-variables theory and has been called into question by several experiments. For example in the double-slit experiment we can see that the spread out wave patterns of the quantum field strength before measurement affect real-world outcomes. This wave state of the quantum field are the best explanation for how the field can interact with itself and produces wave-like interference patterns [This last paragraph has been less polished by me]."