El principi de les caselles (o del colomar) quàntic

He vist al Science News la notícia de la comprovació experimental del Principi Quàntic de les Caselles (o del Colomar). En la seva formulació clàssica, matemàtic, diu que si hi ha dos caselles a un colomar, i hi ha 3 coloms, per força una casella n’ha de tenir un.

Sembla que al món quàntic (o sigui, el real) això no és ben bé així, parlant de polarització de fotons: Photons reveal a weird effect called the quantum pigeonhole paradox:

In the study, three photons took the place of the pigeons. Rather than crowding the photons into holes, the researchers studied the polarization of the particles, or the orientation of the photons’ wiggling electromagnetic waves, which can be either horizontal or vertical. Since there were three photons and two polarizations, standard math would suggest that at least two must have had the same polarization. When the scientists compared the particles’ polarizations, the team found that no two particles matched, verifying that the quantum pigeonhole effect is real.

Així i tot, cal anar amb molt de compte amb fer la mesura:

The study is the first to confirm that quantum pigeons misbehave only under a specific condition. Tollaksen and his colleagues had predicted that, in order for the effect to occur, the measurement of the polarizations must be gentle, so as not to perturb the delicate quantum particles. The new work confirmed that the measurement has to be weak for the effect to occur.

Estic segur que podrem trobar un joc de màgia per explicar aquest efecte, que encara és més enrevessat que no pas el d’entrellaçament de partícules.