bures_distance

forest.benchmarking.distance_measures.bures_distance(rho: numpy.ndarray, sigma: numpy.ndarray) → float

Computes the Bures distance between two states rho and sigma:

\[D_B(\rho, \sigma)^2 = 2(1- \sqrt{F(\rho, \sigma)})\]

where \(F(\rho, \sigma)\) is the fidelity.

Parameters:

• rho – Is a dim by dim positive matrix with unit trace.
• sigma – Is a dim by dim positive matrix with unit trace.

Returns:

Bures distance which is a scalar.