Entanglement-Assisted Communication Surpassing the Ultimate Classical Capacity

Entanglement underpins a variety of quantum-enhanced communication, sensing, and computing capabilities. Entanglement-assisted communication (EACOMM) leverages entanglement pre-shared by parties to boost the rate classical information transmission. Pioneering theory works showed that EACOMM can enable well beyond ultimate capacity optical communications, but an experimental demonstration any advantage remains elusive. Here, we report implementation surpassing over lossy noisy bosonic channels. We construct high-efficiency source phase-conjugate quantum receiver reap benefit entanglement, despite being broken channel loss noise. show beats Holevo-Schumacher-Westmoreland up 14.6%, when both protocols are subject same power constraint at transmitter. As practical performance benchmark, protocol without assistance is implemented, showing reduce bit-error 69% channel. Our work opens route provable advantages in wide range processing tasks.