Scientists call these exotic quasi-particles anyons, and they behave in ways that neither electrons nor photons do.
While this may seem counterintuitive, it actually happens due to quantum mechanics. The catch is that this phenomenon requires strong external magnetic fields, which the researchers wished to avoid.
However, the moiré material tMoTe2 is such that the twist creates an internal magnetic field, allowing the fractional quantum Hall effect to be observed without needing an external magnetic field.
For the optical technique, the researchers use a fast laser pulse that disrupts or melts the quantum states in the material temporarily. Then, a second pulse monitors the recovery of the states.