This property names a type of statement exemplified by one involving the log squared of the Mandelstam variable s, named for Marcel Froissart (“fwah-SAR”). The Wightman axioms entail the existence of a representation of the Poincaré (“pwann-ka-RAY”) group with this property in a QFT’s Hilbert space. Operators with this property cannot copy arbitrary quantum states according to the no-cloning theorem. One of a type of bound named for this property can be derived from the fact that the S-matrix displays it. This property is held by all matrices representing quantum gates and by the time evolution operator. The gauge group of QED is the group of matrices with this property of dimension 1. When multiplied by two vectors, matrices with this property leave the Hermitian (“her-MISH-un”) inner product unaltered. For 10 points, name this property of a matrix whose conjugate transpose is its inverse. ■END■
ANSWER: unitarity [or unitary or unitary matrix or unitary matrices or unitary operators or unitarity operators; accept unitary bound or unitarity bound; accept unitary group; accept unitary representations; prompt on U or U(1)]
<Physics>
= Average correct buzz position