Quantum entanglement generated by sunlight
Scientists have demonstrated that sunlight, as a natural light source, can generate quantum-entangled photon pairs. With their findings, the international research team challenges the long-held assumption that lasers are indispensable for pre-paring quantum states of light. The study recently published in Optica opens a path toward new sustainable and energy-efficient photonic quantum technologies.
Entangled photons are pairs of light particles that remain correlated in ways no classical physics can explain. They are a key resource for quantum communication, computing, and sensing. Such photon pairs are routinely produced through a process called spontaneous parametric down-conversion (SPDC), in which photons from a pump beam are converted inside a nonlinear crystal into pairs of daughter photons.
