Numerical Determination of the Three-Tangle of Mixed States
Sameh M. Saad · Research Repository (Delft University of Technology) · 2015
This thesis presents a numerical method for computing the two-tangle and three-tangle of mixed states.A target function is constructed for both the two-tangle and three-tangle of mixed states, where a number of constraints have been introduced in order to make sure that the whole construct makes physical sense.The target function is then minimized by means of the COBYLA algorithm, and tested by comparison with known analytical results.The numerical computation of the twotangle shows good agreement with the analytical results.As for the three-tangle, it can be reasonably approximated by the COBYLA algorithm, given that the algorithm is allowed to run for some time.Presumably, an increasingly better approximation to the analytical results will be obtained by increasing the allowed computation time.