%0 Journal Article
%T Quantumness Witnesses
%A Robert Alicki
%A Marco Piani
%A Nicholas Van Ryn
%J Mathematics
%D 2008
%I arXiv
%R 10.1088/1751-8113/41/49/495303
%X A recently proposed test of quantumness [R. Alicki and N. Van Ryn, J. Phys. A: Math. Theor. 41 062001 (2008)] is put into a broader mathematical and physical perspective. The notion of quantumness witness is introduced, in analogy to entanglement witness, and illustrated by examples of a single qubit and many-body systems with additive observables. We compare also our proposal with the quantumness test based on quantum correlations (entanglement) and Bell inequalities. A class of quantumness witnesses associated to the phase space representation is also discussed.
%U http://arxiv.org/abs/0807.2615v1