Two different groups have tested a seemingly counter-intuitive property of the quantum world: That it’s possible to put a photon, a particle of light, in a superposition of states going forward and backward in time.This is not time travel and won’t lead to communicating with the past – but it is an intriguing demonstration of how time can be thought to work at a quantum level.This has some fun theoretical applications, for example where an electron moving forward in time can be thought of as a mirrored positron (the antimatter equivalent) going back in time.Recent research suggested that it was possible to have photons in a superposition of states backward and forward in time.The ability to have quantum time flips could allow for better performances and switching inputs and outputs."