Quantum tunneling is a phenomenon where particles pass through a potential energy barrier that they classically shouldn't be able to cross. This happens because of the wave-like nature of particles in quantum mechanics. Even when the energy of the particle is lower than the barrier, there's a probability that it can "tunnel" through and appear on the other side. This is due to the particle's wavefunction extending into and beyond the barrier, allowing it to penetrate and cross over.
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| Image: Artistic illustration of tunnelling | generated by AI |
In quantum mechanics, particles act like waves. These waves can sometimes pass through barriers, even if the particle doesn't have enough energy to go over them. If the barrier is thin or low enough, there's a chance the particle will appear on the other side. This is called "quantum tunneling."
It’s like magic, where a particle goes through the barrier instead of over it.
Imagine you have a ball on one side of a big hill. Normally, the ball needs enough energy to roll over the hill. But in the quantum world, sometimes the ball can magically appear on the other side without rolling over the hill. This magic trick is called quantum tunneling.
Quantum tunneling happens because tiny particles, like electrons, behave both like particles and waves. Their wave-like nature lets them pass through barriers that they shouldn't be able to cross. So, even if a particle doesn't have enough energy to go over the barrier, it can still "tunnel" through it and appear on the other side.
This weird behavior is really important in things like transistors, scanning tunneling microscopes, and even stars! In stars, tunneling helps atomic nuclei fuse together and produce energy.
Applications
Electronics - Tunneling diodes, Transistors
Microscopy - Scanning Tunneling Microscope (STM)
Quantum Computing - Quantum tunneling is integral to certain qubits and quantum gates.
Examples
- Radioactive Decay - Alpha particles tunnel out of the nucleus in radioactive atoms.
- Fusion in the Sun - Protons tunnel to overcome repulsive forces and fuse into helium.
- LEDs and Lasers - Tunneling phenomena improve efficiency in optoelectronics.