What is Power Counting? Exploring its Relationship to Renormalisation

[Bobhawke]

I have heard many people use the term power counting before but I can't find any explanation of what it means. All I know is that it is related to renormalisation somehow. Could someone explain to me what power counting is?

thanks

 

[distanceless]

I hope you can find what you want from this lecture.

http://arxiv.org/abs/nucl-th/0510023

 

[sir-pinski]

Power counting is a technique used in theoretical physics to determine the relative importance of different terms in a mathematical expression. It involves assigning a power (or degree) to each term based on the number of fields or derivatives present in the expression. This allows us to evaluate which terms are dominant and which are negligible in a given physical process.

In the context of renormalisation, power counting is used to determine the divergences in a quantum field theory. These divergences arise due to the infinite number of terms that appear in perturbative calculations. Power counting helps us identify which terms contribute to these divergences and which ones can be neglected. This is important because renormalisation involves removing these divergences to obtain finite and meaningful results.

In simple terms, power counting is a way to organize and simplify calculations in theoretical physics, particularly in the context of renormalisation. It allows us to focus on the most relevant terms and neglect those that have a smaller impact on the physical process being studied.