The sum of the Holevo quantity (that bounds the capacity of quantum channels to transmit classical information about an observable) and the quantum discord (a measure of the quantumness of correlations of that observable) yields an observable-independent total given by the quantum mutual information. This split naturally delineates information about...
Topological defects, such as monopoles, vortex lines or domain walls, mark locations where disparate choices of a broken-symmetry vacuum elsewhere in the system lead to irreconcilable differences(1,2). They are energetically costly (the energy density in their core reaches that of the prior symmetric vacuum) but topologically stable (the whole manifold...