Upper Energy Limit in Field Theory: Exploring Quantum Gravity

In summary, the conversation discusses the use of dimensional analysis and the uncertainty principle to find the Planck length and mass-energy. It is also mentioned that the notion of particles is used to obtain these scales, but there is a question about whether this can be done using fields instead. The conversation also touches on the lack of a valid quantum field theory for gravity and the pursuit of spin foam as a possible model for quantum gravity. However, it is too early to determine if this is the direction that quantum gravity is headed in.
  • #1
victorvmotti
155
5
I see that we use dimensional analysis involving constants of nature to obtain the Planck length and then apply the uncertainty principle to find the corresponding Planck mass-energy.

But the energy and length scales were found by invoking a "particle" interpretation of fundamental entities of nature. Wasn't it?

This is not still clear for me, I mean, where and how we used the notion of particles to obtain Planck scales?

I am not deep into the quantum field theory yet, but if we let go of the notion of particles and introduce the fields (real or complex set of functions of spacetime) instead as the fundamental entities of nature, then can we make sense of arbitrarily large energies or small distances?

But gravity does not still have any valid QFT, it is now a classical theory, so we say for arbitrarily small distances on space, there should be only quantum fields, and therefore we are waiting for quantum gravity?

Am I right in the above argument?
 
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  • #2
Spin foam is where quantum gravity is headed, but apparently it is way out of my "field" of expertise.
 
  • #3
jerromyjon said:
Spin foam is where quantum gravity is headed

It's one possible quantum gravity model that's being pursued, but I think it's way too soon to say that is "where quantum gravity is headed". There are other models, and very, very few testable predictions.
 

1. What is the upper energy limit in field theory?

The upper energy limit in field theory refers to the maximum energy at which the theory can accurately predict and explain physical phenomena. Beyond this limit, the theory breaks down and cannot accurately describe the behavior of particles and fields.

2. How is the upper energy limit determined?

The upper energy limit is determined through experimental evidence and theoretical calculations. Scientists use particle colliders and other high-energy experiments to probe the behavior of particles at increasingly higher energies. Theoretical models also play a crucial role in predicting the upper energy limit.

3. What is the significance of the upper energy limit in field theory?

The upper energy limit is significant because it helps us understand the fundamental nature of the universe. By pushing the limits of our current theories, we can gain insights into the behavior of particles and fields at extreme energies, which can ultimately lead to the development of new theories and a deeper understanding of quantum gravity.

4. How does the upper energy limit relate to quantum gravity?

Quantum gravity is a theoretical framework that aims to unify the theories of general relativity and quantum mechanics. The upper energy limit in field theory is important in this pursuit because it marks the energy at which we expect to see the effects of quantum gravity. Beyond this limit, we may observe phenomena that cannot be explained by our current theories.

5. What are some current efforts to explore the upper energy limit in field theory?

Scientists are currently using high-energy experiments, such as the Large Hadron Collider, to investigate the behavior of particles at extreme energies. They are also developing new theoretical models, such as string theory, to better understand the upper energy limit. Additionally, there are ongoing efforts to develop new technologies and techniques that can push the limits of our current experimental capabilities.

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