- #1

- 764

- 57

If

**A**is a Hermitian operator then

**U**= e

^{iA}is a unitary operator.

To prove this we take the Hermitian conjugate of

**U**

Ue

U

^{+}=^{-iA}= (e

^{iA})

^{-1}(1)

⇒

**U**=

^{+}**U**(2)

^{-1}My question is - In line (1) , -1 is used as an exponent or power while in line (2) , -1 is used to refer to the inverse of a matrix. Are these not 2 different uses of -1 ?

Thanks