2019/12/09 by Art Hobson, Hobson, Art
Computer Science · Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Cold Atom Physics and Bose-Einstein Condensates #FOS: Physical sciences #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum Physics (quant-ph)
paper · pdf · doi:10.48550/arxiv.1912.05439
openalex publication_date 2019/12/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The entangled state that results when a detector measures a superposed\nquantum system has spawned decades of concern about the problem of definite\noutcomes or "Schrodinger's cat." This state seems to describe a detector in an\nindefinite or "smeared" situation of indicating two macroscopic configurations\nsimultaneously. This would be paradoxical. Since all entangled states are known\nto have nonlocal properties, and since measurements have obvious nonlocal\ncharacteristics, it's natural to turn to nonlocality experiments for insight\ninto this question. Unlike the measurement situation where the phase is fixed\nat zero for perfect correlations, nonlocality experiments cover the full range\nof superposition phases and can thus show precisely what entangled states\nsuperpose. For two-state systems, these experiments reveal that the measurement\nstate is not a superposition of two macroscopically different detector states\nbut instead a superposition of two coherent correlations between distinct\ndetector states and corresponding system states. In the measurement situation\n(i.e. at zero phase), and assuming the Schrodinger's cat scenario, the\nentangled state can be read as follows: An undecayed nucleus is perfectly\ncorrelated with an alive cat, AND a decayed nucleus is perfectly correlated\nwith a dead cat, where "AND" indicates the superposition. This is not\nparadoxical.\n