Using a superconducting parametric resonator, physicists have for the first time convincingly confirmed genuine three-particle non-Gaussian entanglement in the emission of a source of three-photon spontaneous parametric down-conversion (SPDC). The entanglement witness (a criterion based on three-mode correlations) violated the classical bound by 23 standard deviations — like a trio of musicians playing in perfect sync without a conductor. The data matched the analytical model precisely, and the choice of temporal shape of the photon pulses strongly affects the result.
Physicists have for the first time created a trio of photons entangled as a single whole, not just pairwise. To achieve this, a special chip was cooled to a temperature hundreds of times lower than that of deep space — any noise threatened to destroy the fragile link. Entanglement of three particles is like three billiard balls rolling in sync, even when placed in different corners of the table: a strike on one instantly changes the behavior of the others, and their shared trajectory seems to ignore the limits of the speed of light.
The mathematical test (an 'entanglement witness') showed a 23-fold excess over random synchrony — as if the balls always bounced off at exactly the same angle with micron precision. The resulting state also turned out to be 'non-Gaussian': its statistics are far from the usual gently sloping curves, as if the balls traced complex vortices, opening new tricks for quantum computing. The experiment confirmed the predictions of the Standard Model, the bedrock of particle physics.
🎯 The method for generating photon pairs, discovered back in the 1960s, has only recently made it possible to reliably create triples with controlled entanglement.
🎬 In the 'Three-Body Problem' trilogy, three celestial bodies move chaotically and unpredictably, while the three quantum photons in the experiment, on the contrary, demonstrate the highest degree of synchrony.