Virtual Particles; Making the Universe an Open System?

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Discussion Overview

The discussion centers around the question of whether the existence of virtual particles implies that the universe is an open system. Participants explore the implications of virtual particles in the context of physics, particularly in relation to their definitions and interpretations within theoretical frameworks.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • The original poster (OP) questions if virtual particles would make the universe an open system and invites responses.
  • One participant suggests searching existing threads on virtual particles, indicating that the topic has been discussed extensively.
  • Another participant questions the premise by asking why virtual particles would lead to the conclusion of an open system.
  • A further participant asks the OP to clarify their definition of an open system, indicating that definitions may vary and affect the discussion.
  • One contributor discusses the mathematical origins of virtual particles, noting their connection to perturbation theory and Feynman diagrams, and raises concerns about their physical existence and implications.
  • This contributor argues that virtual particles lack fundamental evidence and could violate energy-momentum relations, suggesting that they are merely interpretative tools rather than observable entities.
  • Additionally, the same contributor questions the applicability of virtual particles in non-perturbative theories, asserting that they cannot be fundamental concepts in physics.
  • The contributor concludes that, based on their reasoning, virtual particles do not exist and therefore do not challenge the closed nature of the universe.

Areas of Agreement / Disagreement

Participants express differing views on the existence and implications of virtual particles, with no consensus reached regarding their role in defining the universe as an open or closed system.

Contextual Notes

Participants have not established a clear definition of an open system, which may influence the interpretations and conclusions drawn in the discussion. The reliance on perturbation theory and the status of virtual particles as non-observable entities are also points of contention.

Thomas Eaton
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The question here is simple; would the existence of virtual particles make the universe an open system? And if not, why? I thank all who consider this question for their time and would love to hear an answer.
 
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We have tons of threads on virtual particles. I suggest a forum search.
 
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Why would it?
 
To the OP: What is your definition of an open system?
 
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The concept of virtual particles come from the mathematical structure of perturbation theory.
Even more than that, they come from Feynman diagrams, which is a way to interpret the terms in the perturbation in field theory.

This poses two points:

1) Although people interpret some phenomena using this concept there is no fundamental evidence that they really exist. I mean, they are used as tool of interpretation without being connected to any observable directly. Also they would violate energy-momentum relation of special relativity (they are off-shell). One might think that's not a big deal. That's when my second point comes in

2) This is a problem I see which I would be glad if someone has an answer for it. As they come from Feynman diagrams, which come from perturbation theory how would they make sense in a non-perturbative theory? As far as I know they can't (it even makes sense to me that they never will). As a non-perturbative approach is more general, in fact indispensable when dealing with phenomena other than scattering, they cannot be part of the fundamental concepts of physics.

Therefore, my answer is no because there is no virtual particles.
Even if you'd like to consider them (for sake of reasoning), as they are not observable they should put no threat to the closedness of the universe.
 

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