# Hermitian¶

Module: pennylane

class Hermitian(A, wires)[source]

An arbitrary Hermitian observable.

For a Hermitian matrix $$A$$, the expectation command returns the value

$\braket{A} = \braketT{\psi}{\cdots \otimes I\otimes A\otimes I\cdots}{\psi}$

where $$A$$ acts on the requested wires.

If acting on $$N$$ wires, then the matrix $$A$$ must be of size $$2^N\times 2^N$$.

Details:

• Number of wires: Any
• Number of parameters: 1