Double-slit detector

**cmind** · 09-12-2011 05:10 AM

Originally Posted by Jenny5

If I understand that correctly, how would you irrevocably discard/disregard the knowledge and observe the interference pattern return? It sounds like you would get an immediate answer... an then you would never not know.

Remove the filter?

**khh** · 09-12-2011 01:38 PM

Originally Posted by Jenny5

If I understand that correctly, how would you irrevocably discard/disregard the knowledge and observe the interference pattern return? It sounds like you would get an immediate answer... an then you would never not know.

You can record how the particles hit the back wall, but not save the data on which slit they passed through. But I don't know if that would cause the interference pattern to return.

Originally Posted by Wayfaerer

I've heard about the polarization method but I was hesitant to post it because I don't really know what to believe and I have some trouble with it. I heard that you can put things at each slit that changes the polarization of the photon. Then there is another thing that either detects or blocks the photons according to their polarization. If you detect the photon, you know what slit it went though. I was just wondering if this method of polarization detection can show an interference pattern to confirm that the detected particles are actually collapsing a wave function.

I think you and StaySharp are talking about different things. The original question in this thread was how to detect a particle, like an electron, while StaySharp is talking about photons (what makes up light). Particles do not have a polarisation.

**StaySharp** · 09-12-2011 04:10 PM

Originally Posted by khh

I think you and StaySharp are talking about different things. The original question in this thread was how to detect a particle, like an electron, while StaySharp is talking about photons (what makes up light). Particles do not have a polarisation.

Right, particles in the sense of matter with mass do not have a polarisation like light.
However photons are also particles, just without mass. And just like electrons they can be in both the state of an distinct particle and a wave. Otherwise it wouldn't be possible to use both for the DS-experiment.

**khh** · 09-12-2011 08:54 PM

Originally Posted by StaySharp

Right, particles in the sense of matter with mass do not have a polarisation like light.
However photons are also particles, just without mass. And just like electrons they can be in both the state of an distinct particle and a wave. Otherwise it wouldn't be possible to use both for the DS-experiment.

I've never heard anyone state that photons are particles before, only that they can behave like them.

**cmind** · 09-12-2011 09:15 PM

Originally Posted by khh

I've never heard anyone state that photons are particles before, only that they can behave like them.

No, they're actually particles. See the Photoelectric Effect.

**Xei** · 09-12-2011 09:36 PM

No, they're actually waves. See double slit interference.

WHAT IS HAPPENING

**Ne-yo** · 09-12-2011 09:45 PM

Actually they're wave-particles. See wave-particle duality.

**cmind** · 09-12-2011 11:07 PM

^ I was just pointing out that someone saying "well they're not really particles" is incorrect. They have just as much right to be called particles as waves, and vice versa.

**Wayfaerer** · 09-12-2011 11:36 PM

Originally Posted by khh

You can record how the particles hit the back wall, but not save the data on which slit they passed through. But I don't know if that would cause the interference pattern to return.

I think you and StaySharp are talking about different things. The original question in this thread was how to detect a particle, like an electron, while StaySharp is talking about photons (what makes up light). Particles do not have a polarisation.

No, we're talking about the same thing. Photons are included in the OP as they exhibit wave-particle duality.