fotoniparit

Fotoniparit, often translated as photon pairs, refers to two photons that are produced simultaneously and exhibit correlations in certain properties. These correlations can be in polarization, energy, momentum, or arrival time. The concept of photon pairs is fundamental to understanding quantum entanglement, a phenomenon where the quantum states of two particles are linked in such a way that they cannot be described independently, even when separated by large distances.

The generation of photon pairs typically occurs through processes like spontaneous parametric down-conversion (SPDC). In SPDC, a high-energy photon (the pump photon) interacts with a nonlinear optical crystal and splits into two lower-energy photons, often called the signal and idler photons. These photons are born entangled, meaning their properties are intrinsically linked. For example, if the pump photon has a specific polarization, the resulting signal and idler photons might have correlated polarizations, such as being always opposite or always the same.

Research into photon pairs has significant implications for quantum technologies. They are crucial building blocks for quantum communication protocols, such as quantum key distribution, which promises highly secure communication. Furthermore, photon pairs are essential for developing quantum computing, enabling the creation of entangled qubits, the fundamental units of quantum information. Experiments involving photon pairs have also provided key evidence for the validity of quantum mechanics and have been used to test fundamental physics principles, including Bell's inequalities.