Optimization of Modified Quantum Discord in Projector Space

In a pair of correlated quantum systems a measurement in one corresponds to a change in the state of the other. In the process, information is lost. Measurement along which set of projectors would accompany minimum loss in information content is the optimization problem of quantum discord and is an important aspect of a classical to quantum transition because it asks us to look for the most classical states. This optimization problem is known to be NP-complete and is important because discord is defined through it making it a major obstacle on every computation. The standard zero discord condition helps us move to a stronger measure that addresses the correlated observables, in such a context we show that discord minimizes at the diagonal basis of the reduced density matrices and present an analytical expression of the measure.