It’s almost a year since Nicolas Gisin and colleagues at the University of Geneva announced that they had calculated that a human eye ought to be able to detect entangled photons. “Entanglement in principle could be seen,” they concluded.

That’s extraordinary because it would mean that the humans involved in such an experiment would become entangled themselves, if only for an instant.

Gisin is a world leader in quantum entanglement and his claims are by no means easy to dismiss.

Now he’s going a step further saying that the human eye could be used in a Bell type experiment to sense spooky-action-at-a-distance. “Quantum experiments with human

eyes as detectors appear possible, based on a realistic model of the eye as a photon detector,” they say.

One problem is that human eyes cannot se single photons–a handful are needed to trigger a nerve impulse to the brain.

That might have scuppered the possibility of a Bell-type experiment were it not for some interesting work from Francesco De Martini and buddies at the Universityof Rome, pointing out how the quantum properties of a single particle can be transferred to an ensemble of particles.

That allows a single entangled photon, which a human eye cannot see, to be amplified into a number of entangled photons that can be seen. The eye can then be treated like any other detector.

This all looks like fun. The first person to experience entanglement –mantanglement–would surely be destined for some interesting press covereage.

But the work raises an obvious question: why is Gisin pursuing this line? The human eyeball could be put to use in plenty of optics experiments, so why the focus on mantanglement?

Could it be that Gisin thinks there is more to entanglement than meets the eye?

Ref: arxiv.org/abs/0902.2896: Quantum experiments with human eyes as detectors based on cloning via stimulated

emission