CC Problem Beyond the Standard Model

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SUMMARY

The discussion centers on potential solutions to the cosmological constant problem and the discrepancies in quantum field theory (QFT) vacuum energy density, which is 120 orders of magnitude greater than observational data. Participants propose modifications to General Relativity (GR) and QFT, emphasizing the need for either internal changes to their respective formalisms or external frameworks like quantum cosmology and supersymmetry. The link between GR and QFT is also highlighted as problematic, suggesting that a deeper understanding is necessary, potentially through string theory. Schwinger’s source theory is mentioned as a critical perspective on the absence of quantum fields in certain conditions, which could address the discrepancy.

PREREQUISITES
  • General Relativity (GR) principles and modifications
  • Quantum Field Theory (QFT) fundamentals and interpretations
  • Understanding of Schwinger’s source theory
  • Basic concepts of string theory and quantum cosmology
NEXT STEPS
  • Research modifications to General Relativity, focusing on quantum cosmology
  • Explore Schwinger’s source theory in detail
  • Investigate the implications of supersymmetry on vacuum energy density
  • Study the coupling between General Relativity and Quantum Field Theory in curved spacetime
USEFUL FOR

The discussion is beneficial for theoretical physicists, cosmologists, and researchers focused on quantum gravity, as well as anyone interested in the foundational issues surrounding the cosmological constant and the unification of GR and QFT.

lucas_
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Which of the following do you prefer as possible solution to the cosmological constant problem or why QFT computes vacuum energy density that is 120 magnitude more than from observational data? Sometimes I think the metric (1.a) needs to change, but on other days I think QFT needs to change (2.a).. the CC problem would indeed be directly relevant to search for physics beyond the standard model.

http://arxiv.org/pdf/hep-th/0012253v1.pdf

1. A modification of GR. The problem could be either(a) ‘internal’ in the sense that a change is needed in the GR formalism itself (e.g. changing the role of the metric), or
(b) ‘external’ in the sense that GR is still considered effectively correct, but that it needs to be embedded in an extended framework to address the question (e.g. quantum cosmology).

2. A modification of QFT. Again, the problem could be either(a) ‘internal’ in the sense that a change in, or a reinterpretation of, the QFT formalism which gives rise to the vacuum energy is needed (for instance through Schwinger’s source theory), or

(b) ‘external’ in the sense that QFT (the Standard Model) is considered effectively correct as a low energy theory, but needs to be embedded in an extended framework to address the question (e.g. supersymmetry).

3. The link between GR and QFT is problematic. Once more, we see at least two

ways in which this may be the case, either the problem is

(a) ‘internal’ in the sense that the link cannot even be discussed properly due to our limited understanding of the coupling between GR and QFT (e.g. QFT in curved spacetime, and back-reaction), or

(b) ‘external’ in the sense that we due to the limited understanding of the coupling between GR and QFT ought to postpone the problem until we have a theory in which the link is embedded in an extended framework for both GR and QFT since only in such a theory will the problem be completely well posed (e.g. string theory)

Schwinger’s source theory is that in the absence of matter and measurement settings, there are no quantum fields avoiding the 120 magnitude discrepancy, how many even consider this possibility?

Can you add others not mentioned above?
 
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In the Hierarchy Problem. It's related to mass too or why Planck mass fluctuations don't make the higgs much heavier. In the Cosmological Constant problem, it is mass too coming from the quantum fluctuations that are 120 magnitude off to observations. They have in common mass from virtual fluctuations.. won't that give constrains to solutions to both? These are the most severe problems in physics today. What can you guys say about this.
 

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