Quantum tunneling is a phenomenon in the quantum world whereby sub atomic particles pass through barriers forbidden to be passed through by classical physics .


A way to conceptualize this is to imagine a ball and a hill. In classical physics for the ball to get to the top of the hill it needs sufficient energy . if it doesnt have this amount of energy , it cant reach the hill top .

But in quantum mechanics , the ball with a very small probability , can reach the top of the hill without having this sufficient amount of energy.


This effect was predicted in the early 20th century but ots acceptance came in the mid century.

This is due to the wave particle duality of matter and is explained using Heisenberg s principle of uncertainty ( position and momentum of a particle cant be measured with perfect certainty simultaneously.


Quantum tunneling is highly probabilistic . through the schodinger equation we can calculate the probability for a particle to observe quantum tunneling.


As a particle approaches a barrier it is described by its wave function. The square of the wave function gives us the probability of finding a particle at a particular point at a particular time.


QUANTUM TUNNELING IN NATURE


Without quantum tunneling , fusion in the sun would not be able to occur as the temperature of the sun is barely enough to overcome nuclear repulsion but with quantum tunneling. . By virtue of quantum tunnelling and Heisenberg’s uncertainty principle, the protons can “tunnel” through the barrier even given the apparently insufficient temperature and energy.



Alpha decay



Faster than light travel for spin 0 particles


Etc