Photon pairs are more sensitive to rotations than single photons

Quantum states of light have enabled novel optical sensing schemes, e.g., for measuring distance or position, with precisions impossible to achieve with classical light sources such as lasers. The field of quantum metrology has now been pushed even further as a team of researchers showed that photons that are engineered to be entangled in complex spatial structures have, due to quantum phenomena, an advantage for sensing the smallest rotations. The new method allows for more precise measurement than what could be achieved by conventional means.