Witnessing the quantumness of a single system: From anticommutators to interference and discord
Witnessing the quantumness of a single system: From anticommutators to interference and discord
We introduce a method to witness the quantumness of a system. The method relies on the fact that the anticommutator of two classical states is always positive. By contrast, we show that there is always a nonpositive anticommutator due to any two quantum states. We notice that interference depends on …