China and South Africa have just set a new record with the world’s longest quantum communications link, a staggering 12,900 km (8,015 miles) of ultra-secure connection enabled by quantum physics. This unbreakable link utilizes quantum key distribution (QKD) for encryption.
The connection was established between the University of Science and Technology of China (USTC) in Beijing and Stellenbosch University in South Africa, facilitated by the quantum microsatellite Jinan-1. Classical information – images of the Great Wall of China and Stellenbosch – was transmitted, but with a quantum twist: encryption keys encoded into individual photons.
Here’s how it works: Jinan-1 encodes these keys into photons, beams them to ground stations, and once both sides possess a key, secure communication ensues. The “quantum” factor kicks in via the photons’ quantum states, which change upon observation. This means any attempted mid-transmission hack would alter the photon’s state, scrambling the message and alerting the recipient to the breach.
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During testing, Jinan-1 transmitted over 250 million quantum photons per second, generating more than a million secure keys in a single satellite pass. This achievement not only set a new distance record for quantum communication (surpassing the previous 7,600 km record between China and Austria via the Micius satellite) but also demonstrated the satellite’s increased power and reduced size – weighing just 23 kg, a tenth of its predecessor.
The ground stations also underwent significant downsizing, from 13 tonnes to 100 kg. These advancements in satellite and ground station technology could pave the way for a faster, more secure global quantum internet. The breakthrough is detailed in a study published in the journal Nature, with the researchers discussing their work in an accompanying video.
Key stats:
- Distance record: 12,900 km (8,015 miles) – the longest quantum communications link to date
- Photon transmission rate: Over 250 million quantum photons per second
- Secure keys generated: More than a million in a single satellite pass
- Satellite weight: Jinan-1 weighs 23 kg (51 lb), one-tenth of its predecessor, Micius
- Ground station weight reduction: From 13 tonnes to 100 kg (220 lb)
What’s truly remarkable about this record-breaking quantum communications link isn’t just its staggering 8,000-mile reach, but the underlying innovation in miniaturization – the satellite and ground stations are dramatically smaller and lighter, weighing in at a mere 23 kg and 100 kg respectively. This downsizing is the real game-changer, hinting at a more viable path to deploying a globe-spanning, ultra-secure quantum internet that’s both feasible and cost-effective.
