Quantum Filter: From Dirty Bits to Crystal-Clear Randomness ⚡ экспресс
Reliable encryption requires random numbers, but real-world randomness sources often produce predictable sequences. Physicists have shown how a quantum computer can turn such a weak signal into near-perfect randomness, even if it’s compromised. The secret is a lightning-fast procedure: an attacker has only 30 milliseconds to cheat, and their location is limited to within a 4500 km radius. It’s like purifying randomness from a distance.
Modern encryption is unthinkable without truly random numbers. But a standard source can be unreliable or even deliberately corrupted. The solution came from experimenters who built a 98-ion quantum processor—it works like a high-speed filter, turning a 'dirty' signal into one that's crystal-clear and unpredictable. Underpinning this are the discoveries of John Stewart Bell, Alain Aspect, and Anton Zeilinger about quantum entanglement—an instantaneous connection between particles across any distance. Ions inside the processor become entangled and then are measured in a random order, which becomes known only milliseconds before measurement. Due to the speed of light, any interference from more than 4,500 km away couldn't reach the processor within the allotted 30 milliseconds. Even a supercomputer right next to the source would be powerless to slip in a fake. This way, a weak, predictable stream gains high entropy—a measure of unpredictability. The experiment carried out such purification remotely for the first time, confirming that we can only trust randomness when it rests on the foundation of the Standard Model and its quantum laws.
🎯 Previously, amplifying randomness required the source and detector to be in the same lab. This experiment did it remotely for the first time, paving the way for global quantum cryptography.