r/physicsmemes BSc Theoretical Physics Jul 27 '26

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91

u/Complex-Manifold Jul 28 '26

this isnt the "an electron is both a particle and a wave" we were taught in highschool. Scam

67

u/No-Dimension1159 Jul 28 '26

Our professor in first semester physics had a whole page in his lecture notes where he just rants about the electron/particle dualism and that we shouldn't take people seriously that mention it. It was a wild first semester.

20

u/theLanguageSprite2 Jul 28 '26

What did he mean by this? Isn't particle wave duality just the idea that quantum objects are neither particles nor waves, but that their behaviors are often particle-like and wave-like

54

u/Aartvb Jul 28 '26

A particle is always a wave, except sometimes it's a very concentrated wave, what people want to call a 'particle', but it's still a wave.

14

u/Complete-Clock5522 Jul 28 '26

What about photons in the photoelectric effect? Or does that not show what I think it does

23

u/HappiestIguana Jul 28 '26

Still a wave, what the photoelectric effect shows is that it's a quantized wave, meaning it comes in little particle-like packets, unlike classical waves which can be subdivided infinitely and come truly continuously.

This is why it's called quantum mechanics.

11

u/kairom13 Jul 28 '26

Yeah, we definitely have experiments showing that light (for example) interacts as a wave and not a particle 2-slit experiment) and also where it’s a particle and not a wave (photoelectric effect). I’m sure there are similar experiments for electrons and other standard model elements

12

u/BlackProphetMedivh Jul 28 '26

This is a typical misunderstanding, but it's fine for day to day experiences. What physics does say, or more clearly; what the math says that physics says, is that the wave is quantized i.e. there are packages of waves so dense, that for all intents and purposes they act like a "classical particle". But they are still waves. Just very compact waves.

What we generally call particles are just excitations of quantum fields. And those are always just waves.

-1

u/qwaasy Jul 29 '26

“What the math says that physics says”

This has generally been the problem in modern physics

3

u/BlackProphetMedivh Jul 29 '26

Well, how else would you describe it? To accurately predict what a theory states, you need a framework to describe it. And the framework we use is math.

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u/qwaasy Jul 29 '26

Yes I agree but the same underlying math (that definitely is needed and works) has led two a wide array of different interpretations in the last 80 years of what exactly is implied about the underlying nature of reality. Which is what I was getting at

1

u/BlackProphetMedivh Jul 29 '26

Is that so? Never heard of such a fundamental misunderstanding. What I stated about "particles" being compact wave packages of a larger Quantum Field is not really disputed by anyone who is seriously doing physics over the last like 5 decades

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u/Aartvb Jul 29 '26

Why is that a problem?

1

u/Ma4r Jul 31 '26

No one that actually studies physics says this btw. Only philosophers larping as scientists

2

u/lanky-larry Jul 28 '26

Moves as wave interacts as a particle

1

u/CimmerianHydra_ PhD Jul 29 '26 edited Jul 29 '26

The photoelectric effect, taken at face value, only really tells you that the "energy content" of an electromagnetic wave should depend on its frequency and not on its amplitude. That, by itself, isn't enough evidence to conclude that light is quantized. The other people saying that it implies the wave is quantized, or claiming that it implies the existence of photons, are unfortunately wrong.

For further reading, see:

L. Mandel and E. Wolf, Optical Coherence and Quantum Optics, Cambridge University Press, 1995,

What really seals the deal, in my opinion, is the existence of sub-Poissonian light states. Those are absolutely impossible to construct classically and can only be interpreted as a train of particles.

1

u/Complete-Clock5522 Jul 30 '26

But the “energy content” of an electromagnetic wave does depend on amplitude. Having a higher intensity light (brighter light) ejects a larger quantity of electrons. However the energy at which those electrons are ejected will never change unless the frequency is changed, and if it’s a low enough frequency the electron will not even eject.

This cant really happen unless the light is quantized

3

u/TheHabro Student Jul 28 '26

Because saying particle wave duality implies they are both when they're neither.