The wave function of the electron doesn't collapse when passing through air?

  • Context: High School 
  • Thread starter Thread starter cosmanino2050
  • Start date Start date
Click For Summary

Discussion Overview

The discussion revolves around the behavior of the electron wave function in the context of the double slit experiment, particularly focusing on why it does not collapse when electrons pass through air before reaching the detection screen. The conversation touches on experimental conditions, interactions with air molecules, and the implications for wave function behavior.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants question why the wave function of the electron does not collapse when it interacts with air molecules, suggesting that interference patterns still emerge.
  • Others note that experiments are typically conducted in a vacuum to avoid interactions with air molecules, which complicate the results.
  • A participant emphasizes that it is the electron itself that travels, not the wave function.
  • There are inquiries about the minimum vacuum pressure required for the wave function to collapse, with suggestions of various pressures (0.1 kPa, 1 kPa, 10 kPa) being posed.
  • Some participants discuss the probability of electron interactions with air molecules, indicating that there is no definitive minimum pressure for interactions to occur.
  • One participant introduces a hypothetical scenario involving collisions in a classical limit to illustrate the complexities of determining interaction probabilities, mentioning factors like path length and density.
  • Another participant acknowledges the complexity of concepts like mean free path and its dependence on temperature and pressure.

Areas of Agreement / Disagreement

Participants express differing views on the implications of air interactions on the wave function and the conditions under which it collapses. There is no consensus on the minimum pressure required for significant disruption of the electron wave function, and the discussion remains unresolved regarding the specifics of these interactions.

Contextual Notes

Participants highlight the complexities involved in determining interaction probabilities, including factors such as path length, temperature, and density, which may influence the behavior of electrons in various environments.

cosmanino2050
Messages
5
Reaction score
0
TL;DR
Why the wave function of the electron in the double slit experiment doesn't collapse when it passes through air (interacting with its molecules) before reaching the screen, showing the interference pattern?
Why the wave function of the electron in the double slit experiment doesn't collapse when it passes through air (interacting with its molecules) before reaching the screen, showing the interference pattern?
 
Physics news on Phys.org
Such experiments are typically done in a vacuum.
 
  • Like
Likes   Reactions: AlexB23, Dale, FactChecker and 2 others
cosmanino2050 said:
Why the wave function of the electron in the double slit experiment doesn't collapse when it passes through air (interacting with its molecules) before reaching the screen, showing the interference pattern?
As @Doc Al says, experiments with electrons are usually done in a vacuum, precisely because otherwise the electrons would interact with the air molecules that they encounter. The vacuum pumps and vacuum chambers are expensive and hard to maintain so we generally try not to use electrons in our experiments if we can use photons (which don't interact strongly with air and can be moved around in fiber optic cables) instead.
 
  • Like
Likes   Reactions: Cthugha, javisot, Doc Al and 3 others
cosmanino2050 said:
Why the wave function of the electron in the double slit experiment doesn't collapse when it passes through air (interacting with its molecules) before reaching the screen, showing the interference pattern?
Just to stress that it is not the wave function that passes. It is the electron.
 
  • Like
Likes   Reactions: Nugatory
Moderator's note: An off topic and rather contentious subthread has been deleted.
 
  • Like
Likes   Reactions: AlexB23, bhobba and weirdoguy
Quick question folks. What would the weakest vacuum pressure (or air pressure) be that would allow the electron wave function to collapse in a double slit experiment? 0.1 kPa, 1 kPa, 10 kPa?
 
AlexB23 said:
Quick question folks. What would the weakest vacuum pressure (or air pressure) be that would allow the electron wave function to collapse in a double slit experiment? 0.1 kPa, 1 kPa, 10 kPa?
It's about the probability that a single electron interacts with something, like air molecules. There is no minimum. Even in a vacuum the electron could interact with a passing cosmic ray.
 
  • Agree
Likes   Reactions: AlexB23
DaveE said:
It's about the probability that a single electron interacts with something, like air molecules. There is no minimum. Even in a vacuum the electron could interact with a passing cosmic ray.
That is true. But when will roughly 50% of electrons be disrupted?
 
AlexB23 said:
That is true. But when will roughly 50% of electrons be disrupted?
IDK. I'm not qualified or inclined to solve this for you. But I would take a serious look at the classical limit.
Suppose King Kong is shaking a really big box full of baseballs and an MLB pitcher throws one at 100mph through the box. What are the chances that there's a collision. I'm not sure pressure is the only relevant constraint. What about path length, temperature, etc. Maybe density is more useful? Maybe search google for "mean free path".
 
  • Like
Likes   Reactions: PeroK and AlexB23
  • #10
DaveE said:
IDK. I'm not qualified or inclined to solve this for you. But I would take a serious look at the classical limit.
Suppose King Kong is shaking a really big box full of baseballs and an MLB pitcher throws one at 100mph through the box. What are the chances that there's a collision. I'm not sure pressure is the only relevant constraint. What about path length, temperature, etc. Maybe density is more useful? Maybe search google for "mean free path".
Thank you. Yeah, density is temperature and pressure dependent. I have heard of mean free path. Pretty complex stuff if you ask me.
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
1K
  • · Replies 3 ·
Replies
3
Views
5K
  • · Replies 21 ·
Replies
21
Views
2K
  • · Replies 59 ·
2
Replies
59
Views
7K
  • · Replies 23 ·
Replies
23
Views
8K
  • · Replies 20 ·
Replies
20
Views
2K
  • · Replies 28 ·
Replies
28
Views
7K
  • · Replies 18 ·
Replies
18
Views
3K
  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 16 ·
Replies
16
Views
3K