Controlling nonlocality of bipartite qubit states via quantum channels

In this paper, we analyze quantum channels derived from a class of two-qubit states known as the X states. In particular, we consider X states that break the Bell's CHSH condition and then characterize the associated inverse Choi-Jamio & lstrok;kowski maps, which we call nonlocality generating. Interestingly, the region corresponding to nonlocality generating channels shrinks as their stationary state departs from the maximally mixed state. Finally, we demonstrate special cases, where nonlocality can be fully characterized via as little as a single parameter. This approach significantly simplifies the analysis of nonlocality for the X states.