Quantum 101 Episode 1: Wave Particle Duality Explained

You may have heard that light can act like a particle and like a wave. It can bounce off a mirror like a particle, and it can bend and spread out like a wave.

With careful experiments, we can see how light waves can interfere with each other. But did you know that particles can act as waves, too?

This video outlines the concept of wave particle duality, one of the central ideas in quantum mechanics.

Join Katie Mack, Perimeter Institute’s Hawking Chair in Cosmology and Science Communication, over 10 short forays into the weird, wonderful world of quantum science. Episodes are published weekly, subscribe to our channel so you don’t miss an update.

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[cloudpoint]

A particle can be thought of as an interaction between two waves, an event, not an object. That’s why only a measurement that triggers an interaction can detect a particle.

[WingZeroSymphonics]

Yes, the observer being the observed. It’d be interesting to hear about how the fundamental foundation of wave particle duality may have provided the thought experiment for the holographic principle and eventually AdS/CFT.

[martinsoos]

Since we can make photons from both (electron and positron) and (proton and antimatter), and reverse the process, it would be fair to say that whatever they are made of that they are interchangeable. Hence, some rules should apply to both light and particles. I will also agree that dark matter is a possibility rather than just a math mistake.

[neIntangible]

Somewhat in line with the infamous "double-slit experiment"; this as I understand having a single barrier with two closely spaced, side by side, vertically parallel, very thin openings, placed at a specified distance between the beam source (emitter) and the sensitive plate (observer);... Have other barrier opening variations and shapes, like an "X" (criss-cross), or an "O" (donut), or an "H", for example, been tried?
If so, what have the results shown?
For that matter, have barriers been tried and tested, with them made from different materials, having different atomic structure properties, or placing the barrier and/or plate at different angles, or having these structures at differing voltage potentials. with DC +/-, or with AC frequencies? (think grid in a triode).
It is difficult for a layman like myself, to find many answers to these questions I pose online, as all I'm seeing is always referred back as the simplified explanation, first proposed and shown by Thomas Young. WikipediA does give some examples of variations, with gold foils, buckyballs, hydrofoils etc., but still it makes me more curious about other methods that could possibly been overlooked or have been tried and/or passed by.

*Edit: Gramma

[sarveshpadav]

Wait, I always thought electrons were considered point particles. However, in the video, around 2:54, they seem to have a size! Can someone explain this?

[theramansi]

I just had a thought. If sending one particle at time produces the same effect, then the particles sent as stream still aren't interfering with each other, but with only itself.

[christopherfarley]

Have the double slit experiments for light and particles been done in the vacuum of space? To see if the light or particles are not interfering with air or gravity?

[eljcd]

This may sounds weird, but it can get weirder. What happens if you only use one slit?
A interference pattern will appear too. It will take longer, and will be more smared out, but it will form, too.

[otrondal]

At 1:22 you say that electrons are interfering with each other. Is that true? I think electrons only interfere with themselves, which is shown when you send one electron at the time.

[A_GoogIe_User]

2:55 but in QM an electron has zero size, so it is infinitely smaller than a baseball.

[Dyslexic-Artist-Theory-on-Time]

We have the wave particle nature of light and matter in the form of electrons forming an interactive process or what I like to call a blank canvas that we can interact with. When we interact with the light waves by coming in contact with them, we form new photon ∆E=hf oscillations with particles characteristics. As part of an emergent process, this represents a new particle in space and a new moment in time. This is a continuous process unfolding all around us with the spontaneous absorption and emission of light. Within such a process the uncertainty of quantum mechanics would be the same uncertainty we have with any future event. With an emergent uncertain future represented at the smallest scale of this process by Heisenberg’s Uncertainty Principle ∆×∆pᵪ≥h/4π.