2014/11/30 by A. L. O. Bilobran, R. M. Angelo
Computer Science · Mathematics · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Bounded function #Computer science #Epistemology #Mathematical analysis #Mathematics #Measure (data warehouse) #Observable #Philosophy #Physics #Premise #Quantum #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum entanglement #Quantum mechanics #Quantum nonlocality #Separable space #Statistical physics #Theoretical physics #quant-ph
paper · pdf · doi:10.1209/0295-5075/112/40005
published as Europhysics Letters 112, 40005 (2015) · 6 pages, 2 figures, typos corrected, references added; accepted for publication in EPL
openalex publication_date 2015/11/01 · arxiv created 2015/11/10 · arxiv updated 2015/12/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
From the premise that an observable is real after it is measured, we envisage a tomography-based protocol that allows us to propose a quantifier for the degree of indefiniteness of an observable given a quantum state. Then, we find that the reality of an observable can be inferred locally only if this observable is not quantumly correlated with an informer. In other words, quantum discord precludes Einstein's notion of separable realities. Also, by monitoring changes in the reality of a local observable upon measurements on a remote system, we are led to define a measure of nonlocality. Proved upper bounded by discordlike correlations and requiring indefiniteness as a basic ingredient, our measure signals nonlocality even for separable states, thus revealing nonlocal aspects that are not captured by Bell inequality violations.