Comment on `A scattering quantum circuit for measuring Bell's time inequality: a nuclear magnetic resonance demonstration using maximally mixed states'
arXiv:1207.2786 · doi:10.1088/1367-2630/14/5/058001
Abstract
A recent paper by Souza, Oliveira and Sarthour (SOS) reports the experimental violation of a Leggett-Garg inequality (sometimes referred to as a temporal Bell inequality). The inequality tests for quantum mechanical superposition: if the inequality is violated, the dynamics cannot be explained by a large class of classical theories under the heading of macrorealism. Experimental tests of the LG inequality are beset by the difficulty of performing the necessary so-called 'non-invasive' measurements (which for the macrorealist will extract information from a system of interest without disturbing it). SOS argue that they nevertheless achieve this difficult goal by putting the system in a maximally mixed state. The system then allegedly undergoes no perturbation during their experiment. Unfortunately the method is ultimately unconvincing to a skeptical macrorealist, and so the conclusions drawn by SOS are unjustified.
arXiv comment6 pages, 1 figure
References in corpus (5)
- Experimental violation of a Bell's inequality in time with weak measurement
- Violation of the Leggett-Garg inequality with weak measurements of photons
- Violation of a Leggett-Garg inequality with ideal non-invasive measurements
- A scattering quantum circuit for measuring Bell's time inequality: a nuclear magnetic resonance demonstration using maximally mixed states
- NMR Analog of Bell's Inequalities Violation Test
Cited by in corpus (7)
- Leggett-Garg Inequalities
- The Leggett-Garg Inequalities and No-Signalling in Time: A Quasi-Probability Approach
- Violation of Entropic Leggett-Garg Inequality in Nuclear Spins
- The Leggett-Garg inequality in electron interferometers
- Decoherence and maximal violations of the Leggett-Garg inequality
- Leggett-Garg tests of macrorealism: checks for non-invasiveness and generalizations to higher-order correlators
- Leggett-Garg Correlation Functions from Non-Invasive Velocity Measurement Continuous in Time