If you run into a wall, there is a pretty good chance you will not get through it. To break through a barrier you need to energy to overcome it, and sometimes it can take a lot of energy. In quantum mechanics though, if you want to get through a barrier, you do not always need to break through. Instead you can tunnel though, with considerably less energy than is needed to break the wall. Controlling when a particle tunnels is not always easy, but researchers at the University of Cambridge have found a way to do just that.
The researchers trapped some electrons behind barriers they cannot pass through and then shot some light at them. The light was trapped between two mirrors, so it kept passing through the electrons. When the electrons coupled with the photons, a previously unseen particle was created that the researchers are calling dipolaritons. These particles resemble a bar magnet with a stretched out shape and how they interact with each other.
It is the dipolaritons that are then capable of tunneling through the barrier. In effect, the photon teaches the electron how to spontaneously move from one side of the barrier to the other. This could open up new possibilities in many devices, as tunneling is a useful phenomenon. Also the researcher may lead to a better understanding of condensates, which have the ability to travel through semiconductors without resistance, like electrons in a superconductor.