Detection loophole in quantum causality and its countermeasures
arXiv:2107.09261 · doi:10.1103/PhysRevA.104.L010201
Abstract
Quantum causality violates classical intuitions of cause and effect and is a unique quantum feature different from other quantum phenomena such as entanglement and quantum nonlocality. In order to avoid the detection loophole in quantum causality, we initiate the study of the detection efficiency requirement for observing quantum causality. We first show that previous classical causal inequalities require detection efficiency at least 95.97% (89.44%) to show violation with quantum (nonsignaling) correlations. Next we derive a classical causal inequality I_{222} and show that it requires lower detection efficiency to be violated, 92.39% for quantum correlations and 81.65% for nonsignaling correlations, hence substantially reducing the requirement on detection. Then we extend this causal inequality to the case of multiple measurement settings and analyze the corresponding detection efficiency. After that, we show that previous quantum causal inequalities require detection efficiency at least 94.29% to violate with nonsignaling correlations. We subsequently derive a quantum causal bound J_{222} that has a lower detection efficiency requirement of 91.02% for violation with nonsignaling correlations. Our work paves the way towards an experimental demonstration of quantum causality and shows that causal inequalities significantly differ from Bell inequalities in terms of the detection efficiency requirement.
arXiv comment18 pages, 7 figures
References in corpus (24)
- The lesson of causal discovery algorithms for quantum correlations: Causal explanations of Bell-inequality violations require fine-tuning
- Challenging local realism with human choices
- Device independent quantum random number generation
- Beyond Bell's Theorem: Correlation Scenarios
- Local deterministic model of singlet state correlations based on relaxing measurement independence
- Cosmic Bell Test: Measurement Settings from Milky Way Stars
- Cosmic Bell Test using Random Measurement Settings from High-Redshift Quasars
- Genuine quantum nonlocality in the triangle network
- Relaxed Bell inequalities and Kochen-Specker theorems
- Source-independent quantum random number generation
- Theory-independent limits on correlations from generalised Bayesian networks
- Nonlinear Bell inequalities tailored for quantum networks
- Polynomial Bell inequalities
- A unifying framework for relaxations of the causal assumptions in Bell's theorem
- The Inflation Technique for Causal Inference with Latent Variables
- Arbitrarily small amount of measurement independence is sufficient to manifest quantum nonlocality
- Testing Bell's Inequality with Cosmic Photons: Closing the Setting-Independence Loophole
- Non locality, closing the detection loophole and communication complexity
- Cyclic Quantum Causal Models
- Relaxed Bell Inequalities with Arbitrary Measurement Dependence for Each Observer
- Quantifying causal influences in the presence of a quantum common cause
- Bell inequalities violated using detectors of low efficiency
- Measurement-dependence cost for Bell nonlocality: causal vs retrocausal models
- Tight detection efficiency bounds of Bell tests in no-signaling theories