A new method to calculate the inconclusive coefficients in the quantum state discrimination

摘要

The problem of determining the state of a quantum system is a central task in any quantum information processing. However, there are limitations imposed by quantum mechanics on the possibilities to determine the state of a quantum system. For example, nonorthogonal states cannot be discriminated perfectly. In this paper, we propose a new method to calculate the inconclusive coefficients based on the solution of a quadratic system, replacing the determination of the roots of a polynomial of degree 8, used in an algorithm to quantum state discrimination previously defined in the literature. The new method simplifies the calculation of the inconclusive coefficients and can be extended very easily to any dimension. The method was written in Matlab and successfully applied to problems with different dimensions.