  Quantum receivers aim to effectively navigate the vast quantum-state space to
endow quantum information processing capabilities unmatched by classical
receivers. To date, only a handful of quantum receivers have been constructed
to tackle the problem of discriminating coherent states. Quantum receivers
designed by analytical approaches, however, are incapable of effectively
adapting to diverse environment conditions, resulting in their quickly
diminishing performance as the operational complexities increase. Here, we
present a general architecture, dubbed the quantum receiver enhanced by
adaptive learning (QREAL), to adapt quantum receiver structures to diverse
operational conditions. QREAL is experimentally implemented in a hardware
platform with record-high efficiency. Combining the QREAL architecture and the
experimental advances, the error rate is reduced up to 40% over the standard
quantum limit in two coherent-state encoding schemes.
