https://phys.org/news/2019-09-synthetic-hall-effect-one-way-radio.html
"Researchers at the University of Illinois at Urbana-Champaign have replicated one of the most well-known electromagnetic effects in physics, the Hall Effect, using radio waves (photons) instead of electric current (electrons). "
" Instead of an electric current, the team generated a "current of light" by creating synthetic electric and magnetic fields, which affect light the same way the normal fields affect electrons. . . . Although radio waves not carry charge and therefore do not experience forces from electric or magnetic fields, physicists have known for several years that equivalent forces can be produced by confining light in structures that vary in space or time,"
"By creating a specially designed circuit to enhance the interaction between these synthetic fields and radio waves, the team leveraged the principle of the Hall Effect to boost radio signals going in one direction, increasing their strength, while also stopping and absorbing signals going in the other direction."
"Their experiments showed that with the right combination of synthetic fields, signals can be transmitted through the circuit more than 1000-times as effectively in one direction than in the opposite direction. Their research could be used to produce new devices that protect sources of radio waves from potentially harmful interference, or that help ensure sensitive quantum mechanical measurements are accurate."
