[EwanG]

Key quotes from the article:

"This method can enable the simultaneous emission of two photons that are “entangled,” meaning they share the same quantum state even when separated. Such generation of entangled photons is an important element in quantum devices, such as those that might be used for cryptography.

Making use of these forbidden transitions could open up the ability to tailor the optical properties of materials in ways that had not been thought possible, Rivera says. “By altering these rules” about the relationship between light and matter, “it can open new doors to reshaping the optical properties of materials.”"