# Why is wave/particle duality so hard to imagine?

## Main Question or Discussion Point

Why is it difficult (counter intuitive) to imagine an entity (like an electron) that is a particle and a wave? I have seen in many texts/lectures that it is counter intuitive to imagine this sort of thing but I don't understand why.

I have this image in my head that seems to make pretty good sense - it's an extremely small mass that oscillates and vibrates in response to the smallest increments of energy (this includes other waves like light). It also vibrates differently depending on the different types of waves it comes in contact with.

Anyways, it's so small that it's mass can't restrict it from electromagnetic forces that cause it to vibrate and/or be attracted/repelled from other bodies.

How is that hard to imagine? It's late and I think I'm missing something.

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TumblingDice
Gold Member
I think the general analogy you're speaking of is "sometimes acts like a particle, sometimes acts like a wave.". This doesn't mean the object in question actually is one or both. It's something different that can act like either a wave or point/particle. The image you describe doesn't translate well to, for example, interference patterns produced by waves in general.

So it's difficult to imagine because a single object can behave like a wave or a particle. (Not a 'vibrating' or oscillating particle.)

Drakkith
Staff Emeritus
What you are imagining does not correspond to reality. A particle does not physically vibrate like a string does. The wave properties are something that is described by math and cannot be visualized since no waves we've ever seen act like the probability amplitude wavefunction of a particle.

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TumblingDice
Gold Member
The wave properties are something that is described by math and cannot be visualized since no waves we've ever seen act like the probability amplitude wavefunction of a particle.
Is 'probability amplitude wavefunction' in the same conversation as electron behaving like a wave and a particle? I thought QM wave function was a different topic than particle/wave duality. Can you help clear up for me?

vanhees71
Gold Member
2019 Award
The important point is that for about 88 years we don't need "wave-particle duality" anymore but can use a well-defined concept called quantum theory!

ZapperZ
Staff Emeritus
Why is it difficult (counter intuitive) to imagine an entity (like an electron) that is a particle and a wave? I have seen in many texts/lectures that it is counter intuitive to imagine this sort of thing but I don't understand why.

I have this image in my head that seems to make pretty good sense - it's an extremely small mass that oscillates and vibrates in response to the smallest increments of energy (this includes other waves like light). It also vibrates differently depending on the different types of waves it comes in contact with.

Anyways, it's so small that it's mass can't restrict it from electromagnetic forces that cause it to vibrate and/or be attracted/repelled from other bodies.

How is that hard to imagine? It's late and I think I'm missing something.
If I have a stationary electron, it emits an electrostatic field. If I do what you think is happening, i.e. having an electron that "vibrates" as well, then I will generate an electromagnetic radiation, like light! I know this occurs because that is what we get when we cause electrons to pass through a series of undulator/wiggler magnets at a synchrotron light source.

So now, your scenario has a severe experimental deficiency, in which you are missing this extra EM radiation that is a consequence of your scenario. THAT makes it hard to imagine why your scenario would be true.

Zz.

Particle - Wave duality isn't a real physical principle. It just a hand wave way to introduce the idea that in QM objects do not behave according to our naive classic preconceptions. It's often times more trouble than its worth and isn't mentioned at all in most texts directed to more advanced students. Keeping that in mind, it becomes clearer why it can be difficult to actually visualize the duality in any meaningful way. In fact, trying to visualize such an amorphous concept often leads student to develop mental models (such as the one described by the OP) about the nature of particles that end up getting in the way, making the actual learning of QM more difficult. In short, forget about particle wave duality.

I always kinda thought the hard part about comprehending wave-particle duality was the existence of entanglement and violations of bell's inequality, etc. It's not hard to imagine something is a wave like with liquid or made of particulates but the quantum effects make things more noteworthy. Or am I taking it from a different angle than others when they talk about this duality?

Edit: I think duato is on a similar page in the post above. I missed his/her response at the time I wrote mine.