ForceShift

ForceShift does not break the wall. The wall was never quite solid.

A classical ball without the energy to clear a hill rolls back, every time. A quantum particle is a wave, and a wave meeting a barrier it cannot climb does not stop dead at the edge. Inside the barrier it dies away exponentially, and if the barrier is thin enough, a little of it is still there on the far side. That remnant is the chance of getting through. The formula on this page is the standard estimate: the probability falls as e to the power minus twice the barrier width times κ, where κ grows with the square root of the particle's mass and of the energy it is short.

The exponent makes tunnelling touchy. In 1928 George Gamow, and independently Ronald Gurney and Edward Condon, used it to explain alpha decay: the alpha particle is trapped inside the nucleus behind an electric barrier it cannot climb, and leaks out. Compare: polonium-212 releases about 8.95 MeV and has a half-life of 294 nanoseconds. Thorium-232 releases about 4.08 MeV and has a half-life of 14 billion years. A little over twice the energy; about twenty-four orders of magnitude faster. The energy sits inside an exponent.

The Sun runs on the same trick. Its core, about 15.7 million kelvin, is far too cool for two protons to climb over their electric repulsion. They tunnel through it. Then, in a rare few encounters, the weak force turns one proton into a neutron, making deuterium: the first step of the Sun's fusion chain. Tunnelling gets them close; the weak force makes it count.

The scanning tunnelling microscope, recognised by the 1986 Nobel Prize, maps single atoms the same way.

ForceShift does not push harder. They are never entirely on one side.