A sketch note on de Broglie matter waves

Dr. Lalit Kishore, Dean, Science FacultyParishkar College of Global Excellence, Jaipur, India

Key points

Louis de Broglie was a French physicist who proved that all matter can exhibit wave-like behaviour. Later, matter waves concept became central part of the theory of quantum mechanics

The concept that matter behaves like a wave is also referred to as the de Broglie hypothesis and matter waves are often referred to as de Broglie waves.

The de Broglie wavelength is the wavelength, λ, associated with a massive particle and is related to its momentum, p, through the Planck constant, h.

It states that reciprocal of wavelength of a particle is directly proportional to its momentum.

Wave-like behaviour of matter was first experimentally demonstrated in an experiment using electrons.

Earlier, light was found consisting of waves of electromagnetic fields. While matter was thought to be consisting of localized particles; but the idea came under doubt while investigating the theory of black body thermal radiation.

Consequently, Max Planck proposed that light is emitted in discrete quanta of energy. As an extension of the idea, Einstein proposed that light is also propagated and absorbed in quanta or discrete packets of energy.

Combining all the available facts de Broglie proposed that just as light has both wave-like and particle-like properties, electrons also have wave-like properties.

De Broglie waves play an appreciable role, therefore, only in the realm of subatomic particles.

De Broglie waves also exist around a closed loop of atomic particles. For example, such waves are also associated with electrons circling nuclei in atoms like standing waves.