We show how a test of macroscopic realism based on Leggett-Garg inequalities (LGIs) can be performed in a macroscopic system. Using a continuous-variable approach, we consider quantum nondemolition (QND) measurements applied to atomic ensembles undergoing magnetically driven coherent oscillation. We identify measurement schemes requiring only Gaussian states as inputs and giving a significant LGI violation with realistic experimental parameters and imperfections. The predicted violation is shown to be due to true quantum effects rather than to a classical invasivity of the measurement. Using QND measurements to tighten the "clumsiness loophole" forces the stubborn macrorealist to recreate quantum backaction in his or her account of measurement.
CITATION STYLE
Budroni, C., Vitagliano, G., Colangelo, G., Sewell, R. J., Gühne, O., Tóth, G., & Mitchell, M. W. (2015). Quantum Nondemolition Measurement Enables Macroscopic Leggett-Garg Tests. Physical Review Letters, 115(20). https://doi.org/10.1103/PhysRevLett.115.200403
Mendeley helps you to discover research relevant for your work.