Noisy quantum input loophole in measurement-device-independent entanglement witnesses
arXiv:2012.09089 · doi:10.1103/PhysRevA.104.012429
Abstract
Entanglement witnesses form an effective method to locally detect entanglement in the laboratory without having the prior knowledge of the full density matrix. However, separable states can be erroneously indicated as entangled in such detections in the presence of wrong measurements or loss in detectors. Measurement-device-independent entanglement witnesses (MDI-EWs) never detect fake entanglement even under wrong measurements and for a particular kind of lossy detectors. A crucial assumption in the case of faithful detection of entanglement employing MDI-EWs is that the preparation devices producing "quantum inputs" - which are inputs additional to the quantum state whose entanglement is to be detected - are perfect and there is no noise during their transmission. Here, we relax these assumptions and provide a general framework for studying the effect of noise on the quantum inputs, invoking uniform and non-uniform noise models. We derive sufficient conditions on the uniform noisy map for retaining the characteristic of MDI-EWs. We find that in the context of non-uniform and entangling noise, fake entanglement detection is possible even by MDI-EWs. We also investigate various paradigmatic models of local noise and find conditions of revealing entanglement in the class of Werner states.
arXiv comment9 pages, 3 figures
References in corpus (32)
- Quantum entanglement
- Separability Criterion for Density Matrices
- Separability of Mixed States: Necessary and Sufficient Conditions
- Entanglement detection
- Measurement-device-independent quantum key distribution
- Separability criterion and inseparable mixed states with positive partial transposition
- Measurement-based quantum computation
- Bell Inequalities and the Separability Criterion
- Nonsequential positive-operator-valued measurements on entangled mixed states do not always violate a Bell inequality
- Device-independent witnesses of genuine multipartite entanglement
- All Entangled Quantum States Are Nonlocal
- Quantum inseparability as local pseudomixture
- Robust Self Testing of the Singlet
- Reflections upon separability and distillability
- Measurement-Device-Independent Entanglement Witnesses for All Entangled Quantum States
- Experimental detection of entanglement via witness operators and local measurements
- A local hidden variable model of quantum correlation exploiting the detection loophole
- Sufficient conditions for three-particle entanglement and their tests in recent experiments
- Imperfect measurements settings: implications on quantum state tomography and entanglement witnesses
- Entanglement verification and steering when Alice and Bob cannot be trusted
- Detection Loophole in Bell experiments: How post-selected local correlations can look non-local
- Local commutativity versus Bell inequality violation for entangled states and versus non-violation for separable states
- Entanglement verification with realistic measurement devices via squashing operations
- Sequential measurement-device-independent entanglement detection by multiple observers
- Entanglement witnesses and a loophole problem
- Quantum error correction with degenerate codes for correlated noise
- Using macroscopic entanglement to close the detection loophole in Bell inequality
- Complete list of Bell inequalities with four binary settings
- Closing the detection loophole in tripartite Bell tests using the W state
- Device-Independent Bounds on Detection Efficiency
- Beating detection loophole in nonlinear entanglement witnesses
- Detection loophole in measurement-device-independent entanglement witness