Quantum Tunneling: A Shortcut through Barriers

JYP Admin
11 hours ago
3 min read

Author: Soumik Bose

The Source of Quantum Tunneling

We have all been told that everything we see around us is made of minuscule particles and atoms, but have you ever wondered how they actually behave? Although there have been numerous major discoveries in physics, no field has perhaps transformed our understanding as radically as quantum mechanics: the study of how particles behave on the smallest scales.

Quantum mechanics is an inevitable aspect of our everyday life, even if we haven't recognized it everywhere yet. From powering the flash memory in your devices, including the one you are using to read this [1] and maybe even helping you smell the world around you [2]. The key concept of quantum mechanics that makes so much possible is quantum tunneling.

The Development of Quantum Tunneling

Several developments over the 20th century have led to and assisted in the discovery and later utilization of quantum tunneling in 1928 by both Leonid Mandelstam and Mikhail Leontovich independently. To the eye, electrons being able to simply pass through a barrier would seem implausible, as classically a particle would need a huge amount of energy to do this; but in the quantum world it is possible through the nature of electrons. This can be explained through a simple analogy: if we roll a ball up a hill, if it doesn’t have enough energy it will roll back down (this is classical physics). But in the quantum realm, the ball has a chance to appear on the other side of the hill by tunneling through it.

The key to understanding how quantum tunneling works lies within the work of Louis de Broglie, where he theorises that electrons, and matter in general, can have properties of both particles and waves - this is called particle-wave duality. In the classical world we can predict the exact location of electrons, but in the quantum world we can only talk about the probability of where an electron is found. This means that there is a probability, albeit very small, that an electron can be found on one side of a barrier, but also the other. This probability can be worked out using the wave function, which comes from Schrödinger’s equation.

When Tunnelling becomes Useful

As previously mentioned, quantum tunneling is used frequently in our everyday lives. One of the key uses of this is in scanning tunneling microscopes (STMs) [3], this is where electrons tunnel between a probe and the surface of a material, allowing us to research individual atoms, this has been key in expanding and consolidating our knowledge of subatomic structures.

A further key use of quantum tunneling is the development of new materials such as superconductors and nanomaterials, each useful in their own way; superconductors to push the boundaries of clock frequencies and nanomaterials in the targeted delivery of drugs and much more.

Quantum Tunnelling: Small Phenomenon, Big Impact

Quantum tunnelling reminds us that not only the big changes around the world make an impact on us, but also the very minuscule behavior of electrons. It challenges the boundaries of energy conservation and classical physics and gives a new perspective on how atoms work. As more resources go into researching not only quantum tunnelling but the whole genre of quantum mechanics, more breakthroughs are going to occur, because in the quantum world, the boundaries are endless.