Temporal anti-parity–time symmetry offers new way to steer energy through systems

The movement of waves, patterns that carry sound, light or heat, through materials has been widely studied by physicists, as it has implications for the development of numerous modern technologies. In several materials, the movement of waves depends on a physical property known as parity-time (PT) symmetry, which combines mirror-like spatial symmetry with a symmetry in a system's behavior when time runs forward and backwards.