How many electron positron pairs are created

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Discussion Overview

The discussion revolves around the creation of electron-positron pairs in a vacuum, specifically questioning how many pairs are generated per second in a cubic meter. The scope includes theoretical interpretations of vacuum fluctuations and the nature of virtual particles.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • One participant claims that zero electron-positron pairs are created every second in a cubic meter of vacuum.
  • Another participant questions the existence of virtual particles, suggesting they pop in and out of existence in a vacuum.
  • A different viewpoint suggests that these particle-antiparticle pairs are responsible for vacuum fluctuations, although this is noted as speculative.
  • One participant argues against the popular notion of a vacuum as a "sea of particles," stating that no theory supports this idea.
  • Another participant asserts that the vacuum state in quantum field theory (QFT) is stable and does not allow for particles to spontaneously appear or disappear, emphasizing energy conservation.
  • A clarification is made regarding the term "fluctuation," indicating that in quantum mechanics, it refers more to "uncertainty" rather than temporal variation.

Areas of Agreement / Disagreement

Participants express differing views on the existence and nature of electron-positron pair creation in a vacuum, with no consensus reached on the topic.

Contextual Notes

The discussion highlights the speculative nature of certain theories regarding vacuum fluctuations and the definitions of terms used in quantum mechanics, which may lead to misunderstandings.

Admiller
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How many electron positron pairs are created every second in a cubic meter of vacuum?
 
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Zero.
 
Don't these virtual partials pop in and out of existence in a vacuum?
 
Admiller said:
Don't these virtual partials pop in and out of existence in a vacuum?
Google "quantum foam" and you'll see the speculative nature of that theory.
 
Quantum foam does seem very speculative but aren't these particle antiparticle pairs responsible for vacuum fluctuations?
 
The short answer is that you've been lied to. No theory describes the vacuum as that "sea of particles constantly popping into and out of existence" that popsci authors (and some overly romantic actual-sci ones) seem to like so much.
 
The vacuum state, by definition, is the one state in QFT which is absolutely stable, and nothing pops in and out of existence, because it's the ground state, the state of lowest energy. If there's no energy above the ground state there's nothing excited which could pop out of existence again nor can there be anything pop into existence spontaneously, because energy is conserved.
 
In normal language, the word "fluctuation" means "variation with time". In QM language, it's more like a synonym for "uncertainty" or "indefiniteness." Vacuum fluctuation does not involve variation with time.
 

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