Quantum Mechanics demystified, a try
In tunneling phenomenon, an elementary particle jumps over a barrier in an incomprehensible way. Incomprehensible at least from classical mechanics’ point of view. Looking at it Quantum Mechanically, it is just the particle’s wavefunction probability giving the particle a change of appearing on the other side of the barrier in some exceptional cases.
Tunneling is taking place e.g. in the Sun, making it possible for the Sun to produce all that energy by hydrogen->helium fusion.
In this fusion, protons of two hydrogen atom’s nuclei get very, very close to each other, due to the enormous heat around.
But there still is the barrier of rebelling coulomb forces between the positive charges of nuclei protons. This barrier is in some cases crossed over, as the wave function has a tiny probability of the proton existing on the other side of that barrier. Once the barrier is crossed, a fusion of those two protons take place due to attracting strong nuclear force. A Helium atom is born. With a lot of energy as gamma rays released along with some subatomic particles.
On the way out from Sun’s core, gamma rays are giving energy to a plethora of objects. On the very surface of the sun, gamma rays make electrons of metals and other materials there to excite. When this excitation gets discharged, a photon is emitted, including the visible light ones we humans are able to perceive.
In double slit experiment similar thing to tunneling seems to go on. Wave function for the photon allows part of photon’s ‘energy’ go through one slit and some goes through the other. Building up the interference on the other side. See Double slit experiment’s single photon interference
Doesn’t sound so mysterious at all to me. I must have misunderstood the whole thing, Feynman might suggest. ;-)