unitarity

English

Etymology tree

English unit

Proto-Indo-European *-eh₂

Proto-Indo-European *-os?

Proto-Indo-European *-o-

Proto-Indo-European *-so-

Proto-Indo-European *-eh₂so-

Proto-Indo-European *-yós

Proto-Indo-European *-eh₂s(i)yós

Proto-Italic *-āsijos

Proto-Italic *-āsios

Latin -āriusder.

Middle English -arie

English -ary

English unitary

Proto-Indo-European *-teh₂

Proto-Indo-European *-ts

Proto-Indo-European *-teh₂tsder.

Latin -itās

Old French -itebor.

Middle English -ite

English -ity

English unitarity

From unitary + -ity.

unitarity (countable and uncountable, plural unitarities)

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.

(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.

representation by a unitary operator

Greek: μονοτέλεια f (monotéleia), rare: μονοπιθανοτικότητα f (monopithanotikótita)