Meaning of Single Photon Interference Minima

Click For Summary

Discussion Overview

The discussion revolves around the interpretation of minima in the interference pattern observed in the double slit experiment when photons are sent one at a time. Participants explore the implications of single photon behavior, the nature of interference, and the relationship between photons and their wave functions.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions whether a single photon can destructively interfere with itself, leading to the possibility that energy could "disappear" if it does not land on the wall in the bright bands defined by interference.
  • Another participant clarifies that the appearance of minima indicates regions of low probability for detecting the photon, emphasizing that the photon must land somewhere and that energy does not disappear.
  • It is noted that the interference pattern redistributes photons, resulting in more detections at maxima and fewer at minima, without any loss of photons or energy.
  • A participant suggests that the interference involves two wave functions describing the photon as it passes through each slit, prompting questions about the distinction between the photon and its wave function.
  • Another participant asserts that photons do not have a wave function, suggesting a focus on electrons instead, and claims that the double slit experiment does not fundamentally relate to waves.
  • One participant explains that while a single photon results in one spot on the detection medium, firing multiple photons creates a pattern that reflects the wave function's interference effects.

Areas of Agreement / Disagreement

Participants express differing views on the nature of photons and their wave functions, as well as the interpretation of interference patterns. There is no consensus on the relationship between photons and their wave functions or the implications of destructive interference.

Contextual Notes

Some statements rely on specific interpretations of quantum mechanics, and the discussion includes assumptions about idealized experimental conditions. The nature of wave functions in relation to photons versus electrons remains unresolved.

LikesIntuition
Messages
51
Reaction score
1
In the double slit experiment, when we send out one photon at a time, what does the appearance of minima in our interference pattern mean? When a single photon is fired, I understand (using "understand" very loosely) that the photon will interfere with itself. When this happens, does it still have to land on the wall in front of the slit and it is limited to the bright bands defined by interference, or are there times where we will fire the photon and it will destructively interfere with itself and we won't see it land on the wall? Because if that's the case, energy would just be disappearing.

I can try to clarify if need be.

Thanks!
 
Physics news on Phys.org
LikesIntuition said:
In the double slit experiment, when we send out one photon at a time, what does the appearance of minima in our interference pattern mean?
It means that there are regions where the probability of detecting the photon is very low.

LikesIntuition said:
When this happens, does it still have to land on the wall in front of the slit and it is limited to the bright bands defined by interference, or are there times where we will fire the photon and it will destructively interfere with itself and we won't see it land on the wall?
In an idealized experiment, the probability of detecting the photon must be one. It is the probability amplitude (i.e., the wave function) that will show areas of constructive or destructive inteference. It is not the photon interfering with itself.
 
The interference pattern redistributes the photons (and the energy that they carry) so that there are more of them in the maxima and fewer of them in the minima, than we would expect if there were no interference. No photons or energy "disappear".
 
Alright, so every time we send a photon through the double slit, we will detect one after the slit? And it's two wave functions describing the photon as it moves through each slit that interfere with each other?

If that's the case, what's the difference between talking about the photon and it's wave function?
 
Well actually, without going into the details, you don't have a wave-function for photons.

But the double slit can be done with electrons so let's consider that instead.

The wave-function encodes all the quantum properties of the electron.

Also you may like to see an actual quantum explanation of the double slit:
http://cds.cern.ch/record/1024152/files/0703126.pdf

Interestingly it hasn't really got anything to do with waves.

Thanks
Bill
 
LikesIntuition said:
If that's the case, what's the difference between talking about the photon and it's wave function?

In the double-slit experiment, when you fire one photon you get one spot on the photographic film behind the slits. You'll say that one spot is where the particle hit, and we're talking about the particle not the wave function.

As you fire more photons more spots on the film will appear; these spots will gradually build up a pattern of dark and light regions corresponding to the areas of constructive and destructive interference. Now we're talking about the wave function.
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 32 ·
2
Replies
32
Views
4K
Replies
55
Views
6K
  • · Replies 15 ·
Replies
15
Views
1K
  • · Replies 17 ·
Replies
17
Views
2K
  • · Replies 24 ·
Replies
24
Views
4K
  • · Replies 28 ·
Replies
28
Views
2K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 14 ·
Replies
14
Views
4K
  • · Replies 81 ·
3
Replies
81
Views
7K