[sliken]

Along similar lines, the double-slit experiment, seems simple. Two slits let light though and you get bands where they constructively or destructively interfere, just like waves.

However I still find it crazy that when you slow down the laser and one photon at a time goes through either slit you still get the bands. Which begs the question, what exactly is it constructively or destructively interfering with?

Still seems like there's much to be learned about the quantum world, gravity, and things like dark energy vs MOND.

[ggm]

I had a conversation about this in HN some months back. It's a surprisingly modern experiment. It demanded an ability to reliably emit single photons. Young's theory may be 1800 but single photon emission is 1970-80.

(This is what I was told, exploring my belief it's always been fringes in streams of photons not emerging over repeated applications of single photons and I was wrong)

[lefra]

To get single photons, you just need to stack up enough stained glass infront of a light source. That's been acheivable for aeons (the photon will go through at random time though).

The difficult part is single photon _detectors_, they're the key technology to explore the single-photon version of Young's experiment (which originally showed that light has wave-like properties).

[jasonwatkinspdx]

The most simple answer here is the "fields are real, particles are excitation patterns of fields." And that's generally the practical way most physicists think of it today as I understand it.

If I make the equivalent of a double slit experiment in a swimming pool, then generate a vortex that propagates towards my plywood slits or whatever, it's not really surprising that the extended volume of the vortex interacts with both slots even though it looks like a singular "particle."

[el_nahual]

And yet if you place a detector at the slits to know which slit the single photon goes through, you get no interference pattern at the end.

[squeefers]

> However I still find it crazy that when you slow down the laser and one photon at a time goes through either slit you still get the bands.

why does nobody mention the fact the photon doesnt keep going through the same hole? like why is it randomly moving through the air in this brownian way? the laser gun doesnt move, the slit doesnt move, so why do different photons end up going through different holes?