Guillaume Adenier

Is the fair sampling assumption supported by EPR experiments

We analyse optical EPR experimental data performed by Weihs et al in Innsbruck 1997–1998. We show that for some linear combinations of the raw coincidence rates, the experimental results display some anomalous behaviour that a more general source state (like non-maximally entangled state) cannot straightforwardly account for. We attempt to explain these anomalies by taking account of the relative efficiencies of the four channels. For this purpose, we use the fair sampling assumption, and assume explicitly that the detection efficiencies for the pairs of entangled photons can be written as a product of the two corresponding detection efficiencies for the single photons. We show that this explicit use of fair sampling cannot be maintained to be a reasonable assumption as it leads to an apparent violation of the no-signalling principle.

Anomalies in EPR‐Bell Experiments

A new analysis of the Weihs et al 1998 experimental raw data is given. Using a new normalization procedure based on the statistics of the single counts, we investigate seemingly unimportant anomalies in the coincidence count rates. We show that interpreting these anomalies within a quantum mechanical framework is problematic as they imply that the fair sampling assumption is untenable.

Local Time Dependent Instruction‐Set Model for the Experiment of Pan et al

We present an objective local model, based on instruction sets and time dependent equipment parameters that can be used to approximately reproduce the data of the Pan et al experiment and even the quantum mechanical predictions. Our mathematical model includes all experimental provisions of the actual experiment and excludes all the physically unlikely effects that have been known previously to produce violations of Bell‐type inequalities such as synchronization of source parameters with equipment settings. In particular, our model demonstrates that the mathematical assumption that the random variables can be defined on one common probability space plays the most essential role in the construction of so called objective local models more so than the physical assumption of Einstein locality.

Violation of Bell Inequalities as a Violation of Fair Sampling in Threshold Detectors

Photomultiplier tubes and avalanche photodiodes, which are commonly used in quantum optic experiments, are sometimes referred to as threshold detectors because, in photon counting mode, they cannot discriminate the number of photoelectrons initially extracted from the absorber in the detector. We argue that they can be called threshold detectors on more account than that. We point out that their their functioning principle relies on two thresholds that are usually thought unimportant individually in the context of EPR‐Bell discussion. We show how the combined effect of these threshold can lead to a significant sampling selection bias in the detection of pairs of pulses, resulting in an apparent violation of Bell inequalities.

Test of the no-signaling principle in the Hensen loophole-free CHSH experiment

We analyze the data from the loophole-free CHSH experiment performed by Hensen et al., and show that it is actually not exempt of an important loophole. By increasing the size of the sample of even ...

Double blinding-attack on entanglement-based quantum key distribution protocols

We propose a double blinding-attack on entangled-based quantum key distribution protocols. The principle of the attack is the same as in existing blinding attack except that instead of blinding the detectors on one side only, Eve is blinding the detectors of both Alice and Bob. In the BBM92 protocol, the attack allows Eve to get a full knowledge of the key and remain undetected even if Alice and Bob are using 100% efficient detectors. The attack can be easily extended to Ekert protocol, with an efficiency as high as 85.3%.

A Fair sampling test for Ekert's protocol.

We propose a local scheme to enhance the security of quantum key distribution in Ekert protocol (E91). Our proposal is a fair sampling test meant to detect an eavesdropping attempt that would use a biased sample to mimic an apparent violation of Bell inequalities. The test is local and non disruptive: it can be unilaterally performed at any time by either Alice or Bob during the production of the key, and together with the Bell inequality test.

Ion Trap Experiments on Entanglement: The Low Visibility Case

We show that an explicit mixture of separable states can exhibit a correlation that differs from the prediction for an entangled state only by its visibility (1/2 instead of 1). We thus argue that experiments with low visibility (about 1/2 or less) between remote systems can be given a local interpretation within the framework of Quantum Mechanics, and should thus only be regarded as a proof of entanglement with caution.

Fair sampling and rotational invariance in EPR experiments

We have previously shown that the use of the fair sampling assumption in EPR experiments could be questioned on the basis of experimental data. We continue our analysis of the data from the optical EPR experimental performed by Weihs et al. in Innsbruck 1997-1998, and we discuss whether a non-rotationally invariant source can account for the experimental results.

Fair Sampling vs No-Signalling Principle in EPR experiments

We present some recent results of a new statistical analysis of the optical EPR experiment performed by Weihs et al in Innsbruck 1997-1998. Under the commonly used assumption of fair sampling, we s ...