✎ Infrared Divergences [The Physics Travel Guide]

You've loaded an old revision of the document! If you save it, you will create a new version with this data.

====== Infrared Divergences ======

<note tip>
Explanations in this section should contain no formulas, but instead colloquial things like you would hear them during a coffee break or at a cocktail party.
</note>
  
<tabbox Student>

<note tip>
In this section things should be explained by analogy and with pictures and, if necessary, some formulas.
</note>
 
<tabbox Researcher>

<blockquote>Scattering amplitudes in perturbative QED and gravity suffer
from infrared divergences. These well understood divergences arise from our inability to distinguish
between a “hard” particle with or without “soft hair”. (In non-abelian theories there are also collinear IR divergences. As these are absent in QED (and also in
gravity) we will not discuss them here.) Hence, a physical asymptotic
state entering any scattering process is a super-position of the hard particle with all possible
soft hair arrangements. The way to construct the physical asymptotic states that yield an IR
safe S-matrix was put forward by [[https://link.springer.com/content/pdf/10.1007/BF01066485.pdf|Kulish and Faddeev [10]]]. In their construction, the dressed
incoming and outgoing states diagonalize the interacting asymptotic Hamiltonian. Once the
S-matrix of these dressed electrons is expanded in perturbation theory, the cancellation of
IR divergences is ensured by the existence of soft theorems.<cite>https://arxiv.org/pdf/1607.08599.pdf</cite></blockquote>

--> Example1#

<--

--> Example2:#

<--

</tabbox>

Please solve the following equation to prove you're human. 172 -5 = Please keep this field empty:

Edit summary

Note: By editing this page you agree to license your content under the following license: CC Attribution-Share Alike 4.0 International

User Tools

Site Tools

Page Tools