Quantum resonance. Computer model showing quantum resonance. A quantum wavefunction is seen as the parallel waves moving up from bottom. They hit a barrier (black, lower centre). The wavefunction, which describes a particle such as an electron, diffracts through the central hole in the barrier. The waves then reflect from the next, semicircular barrier, and bounce around in the cavity. Usually, only small amounts of waves go through the hole, but if the wavelength matches the size of the cavity, then electrons of that wavelength (energy) accumulate (resonate) in the cavity. Some waves (green) diffract past the barriers. This model was created as an artwork by Professor Eric Heller.