About what can be witnessed by a Leggett—Garg inequality test: modeling its violation

Emergent Quantum Mechanics 2015

Moreira, Saulo V.^1 ; Keller, Arne^2 ; Coudreau, Thomas^1 ; Milman, Pérola^1

Univ. Paris Diderot, Sorbonne Paris Cité, Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162, CNRS, Paris

F-75205, France^1

Univ. Paris Sud, Institut des Sciences Moléculaires d'Orsay (UMR 8214 CNRS), Orsay

F-91405, France^2

关键词: Invasiveness;    Operational model;    Physical systems;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/701/1/012029/pdf
DOI  :  10.1088/1742-6596/701/1/012029

来源: IOP

【 摘 要 】

The Leggett-Garg inequality is a widely used test of the "quantumness" of a system, and involves correlations between measurements realized at different times. According to its widespread interpretation, a violation of the Legget-Garg inequality disproves macroscopic realism and non-invasiveness. Nevertheless, recent results point out that macroscopic realism is a model dependent notion and that one should always be able to attribute to invasiveness a violation of a Legget-Garg inequality. This opens some natural questions: how to provide such an attribution in a systematic way? How can apparent macroscopic realism violation be recast into a dimensional independent invasiveness model? The present work answers these questions by introducing an operational model where the effects of invasiveness are controllable through a parameter associated with what is called the measurability of the physical system. Such a parameter leads to different generalized measurements that can be associated with the dimensionality of a system, to measurement errors or to back action.