Waves and Particles in Light and Matter

John A. Gowan

In 1923 Louis de Broglie introduced the notion of matter waves, the particle-wave duality of matter which is the reciprocal extension of the notion of the particle-wave duality of light. The wave nature of matter is evidently a memory of its origin in light, much as the particle aspect of light suggests its capacity to create matter. Such dualities are part of the connective tissue of the Cosmos and its two principle energy forms, light and matter (free and bound electromagnetic energy). The less massive the particle, the more strongly is its wave nature expressed. The wave nature of the tiny electron is very pronounced, as is famously demonstrated by the interference phenomena of the canonical 2-slit experiment of quantum mechanics. In the extreme case of neutrinos, which apparently have almost no mass, their wave nature completely dominates their particle nature. However, as particles become heavier and more massive, their wave nature becomes rapidly overwhelmed, until for ordinary macroscopic masses to which we are sensible it is completely obscured.

Yuping Huang

Nuffield Advanced Physics team, Jon Ogborn

Časlav Brukner, Anton Zeilinger

Stationary matter wave optics and stationary light optics are equivalent when we consider one-particle systems in vacuum. We show that, in contrast, stationary optics of energy-entangled particles is completely different for matter waves and for light. This difference is illustrated comparing the two-particle interference patterns exhibited by matter waves and by light, respectively. The time-independent probability for simultaneous detection of the two massive particles or of the two photons is strikingly nonequivalent.

Peiman Ghasemi

Today scientists believe that all “particles” also have a “wave nature” (and vice versa). This phenomenon has been verified not only for elementary particles, but also for the elementary particles that exist in compound particles like molecules and even atoms. You can consider light (the photons of the light beams) as a “wave-like energy”. This energy is a wave–particle, just containing elementary matter and speed. We can use Einstein, Planck equations to determine the amount of the energy which make up a sample photon. But, to date we cannot measure the matter, therefore we make a simple unit that let us to measure the matter.

Reinhart Poprawe, Konstantin Boucke, Dieter Hoffman