# How are number theory and C*-algebras connected?

I came across this research profile where under Research Overview, it states that

These days C*-algebra theory is a very active area of mathematical research in its own right, and enjoys deep connections with other areas of mathematics such as symbolic dynamics, ergodic theory, group theory and even number theory.

My question is how C*-algebras and number theory are connected and if this is an active area of research?