Particle - Wave Duality
What can you tell me about wave particle
duality? I have checked the archives and there are various
references but nothing specific.
See Wikipedia for fine discussion of the subject.
Particle-wave duality is at the foundation of Quantum Mechanics.
Simply stated particles have wavelength and light has momentum. We
know of course that particles have momentum and that light has a
wavelength. The duality is that each has characteristics of the other.
The duality was postulated by de'Broglie, momentum is proportion to
the inverse of the wavelength-the proportional constant is Planck's constant.
There seems to have been an interesting exchange of letters between
de'Broglie and Einstein at that time (1915ish). I recall that Big Al
thought the hypothesis was incredibly insightful-de'Bbroglie's
advisors were not so positive.
In some very real way duality lead directly to the Scroedinger
equation, well at least conceptually for me.
In classical physics, in the world we see from day to day, everything is
either a wave or a particle. Water is a group of particles called
molecules. Radio signals are waves. The properties of a wave are very
different from the properties of particles. A particle has a specific
position and a specific size. Particles cannot pass through other
particles. Waves have a specific frequency. Waves can pass through other
waves with no trouble at all.
When you look at things on a very small scale, such as an individual
electron, this separation of waves from particles ceases to exist. All
things are just bundles of energy. Each object can behave more like a wave
in some cases and more like a particle in other cases. At this scale,
called the quantum scale, all things have a frequency. All things can pass
through other things. All things can be measured to be at a position. All
things can bounce off other things. Exactly which properties will be seen
depends on the situation and on how measurements are done.
Dr. Ken Mellendorf
Illinois Central College
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Update: June 2012