A Beginner's Guide to Quantum Tunneling: Breaking Through the Walls of Classical Physics

Imagine a hill in front of you with the top of the hill having potential energy Y for mass M. 

Now push a ball with mass M using X kinetic energy.

If the X<Y: The ball ends up on the other side of the hill.

If X>Y: The ball rolls up and comes back.

If X=Y: The ball rolls up and stays stationary.

This was the classical physics result. In fact, if we throw a particle at a potential barrier and even if it doesn't have enough kinetic energy it can sometimes end up on the other side. This is known as Quantum Tunneling.

The probability wave approaching two barriers.

As the wave collides with the first barrier we see a small chance of the particle being inside the potential barrier.

During the collision we see a small chance of it being on the other side of the potential barrier.

This is known as quantum tunneling.

At time 0.000114 we see a high probability of quantum tunneling. This will slowly decline as the wave gets reflected.

(Pictures courtesy of: https://www.youtube.com/watch?v=MMVKuT2GmXo)

I wont dive into the deep mathematics of quantum tunneling as it is a beginner post. I am going to however look at some real life impacts.

Our sun's seemingly limitless energy is derived from a mind-bending process known as nuclear fusion. Normally, the positively charged protons in hydrogen atoms, the sun's fuel, resist one another strongly. To overcome this reluctance and fuse, they would require extremely high temperatures. But the strange realm of quantum physics throws a surprise. Protons act similarly to waves, and these waves have a small but significant probability of "tunneling" past the repulsive barrier and fusing even at the sun's slightly lower core temperature. This quantum tunneling process is similar to a subatomic magic trick, and while the likelihood of it occurring for any given pair of protons is low, the sun's immense size comes to the rescue. With a massive number of hydrogen atoms continually interacting, these unlikely tunnelings accumulate. Successful fusions unleash enormous amounts of energy, triggering a chain reaction that will keep our sun glowing brilliantly for billions of years.

 

This is how humans are kept alive, with quantum tunneling!

This is all that a beginner needs to know for their quantum journey!

Thank you all for reading!