Scalable Large-Size Quantum State Generation Heralds Practical Quantum Optics

Among all quantum systems, photons are known for their weak interaction, which allows long coherence time to be achieved even at room temperature, making them suitable for transmitting qubits between distant locations. However, the weak interaction of photons restricts the generation of quantum states known as multiphotonic qubit states, or “N-photon states.” Generating N-photon states remains a fundamental challenge in the field of quantum optics. In response, researchers from Nanjing University have proposed a scheme that could generate multiphotonic qubit states deterministically, so that photon number doubling happens with 100% efficiency, with an unlimited numbers of photons. The scheme is experimentally feasible,...