Why in the news?

• The Nobel Prize for Physics this year will be awarded to three scientists — John Clarke, Michel Devoret and John Martinis, the Royal Swedish Academy of Sciences for developing a device showing ‘quantum tunnelling’.

Quantum Tunnelling

• What is it?:
  • Quantum tunnelling is a quantum mechanical phenomenon where a particle passes through an energy barrier that it classically should not be able to cross.
  • It occurs due to the wave–particle duality of matter — particles behave like waves and have a finite probability of being found beyond the barrier.
• How does it work?:
  • In classical physics, a particle cannot cross a barrier if its energy is less than the barrier’s potential energy.
  • In quantum mechanics, the wave function describing the particle extends beyond the barrier.
  • Thus, there is a non-zero probability that the particle “tunnels” through it — appearing on the other side without having enough energy to climb over it.
• Significance:
  • Challenges classical determinism, proving that subatomic particles can behave probabilistically.
  • Foundation of many modern technologies and quantum theory applications.