Quantum Correlations Relativity for Continuous Variable Systems

Abstract: It is shown that a choice of degrees of freedom of a bipartite continuous variable system determines amount of non-classical correlations (quantified by discord) in the system's state. Non-classical correlations (that include entanglement as a special kind of correlations) are ubiquitous for such systems. For a quantum state, if there are not non-classical correlations (quantum discord is zero) for one, there are in general non-classical correlations (quantum discord is non-zero) for another set of the composite system's degrees of freedom. The physical relevance of this 'quantum correlations relativity' is emphasized also in the more general context.