unitarity

English

Etymology

From unitary +‎ -ity.

Noun

unitarity (countable and uncountable, plural unitarities)

1. The quality or state of being unitary.
   • 1993, George Sterman, An Introduction to Quantum Field Theory, page 334,

     In this section, we shall prove the gauge invariance and unitarity of the physical S-matrix in quantum electrodynamics, to all orders in the renormalized perturbation theory.

Usage notes

• (quality or state): The synonymous noun unitariness exists as well, but unitarity and unitariness are each preferred (at least partly) in different fields. Overall, unitarity is more common than unitariness.

Derived terms

• unitarity operator, unitarity triangle