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Open Access. Powered by Scholars. Published by Universities.®

2017

Utah State University

Photons

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Full-Text Articles in Physics

Many-Particle Systems, 5, David Peak Aug 2017

Many-Particle Systems, 5, David Peak

Many Particles

Photons as T → 0 K

Photons are massless bosons. Because they are massless, any number of them can be added or subtracted without changing the photon system energy. (For example, a 1 eV photon can be exchanged for one hundred 0.01 eV photons, without changing system energy.) As a result, the chemical potential for photons is zero.


Foundations, 2, David Peak Aug 2017

Foundations, 2, David Peak

Foundations

The double slit experiment in dim light – photons!

Let’s imagine doing the double slit experiment again, but now in very dim light. To do so requires putting the laser, plate, and collector in a sealed, light-tight box. Inserting neutral density filters in the beam between the laser and the double slit plate decreases the intensity of the beam striking the plate. In fact, the experiment can be done at such a low intensity that a human eye will not see any light on the CCD collector; but the CCD can. Under these conditions, the number of pixels that “light …