Consider a photon described by an out of phase pair of components
that are almost perfectly anti-symmetric so that
for all quarks except down quarks. Many photon attributes are nil because phase anti-symmetry implies that almost every quark is matched with a corresponding anti-quark somewhere in the photon. So for most types of quark Z, the net number of quarks is zero
As for the down-quarks, is not zero. But recall that by convention, the internal energy of down-quarks is so small that it is usually taken to be zero. Then any imbalance between ordinary down quarks and down anti-quarks can be ignored. Substituting these conditions into the definitions for charge, strangeness, lepton number, baryon number and enthalpy gives

Recall that the lepton-number, baryon-number and charge are conserved, so a particle may freely absorb or emit countless photons without altering its own values for these quantum numbers. No work is required to assemble a photon because the two phase components
and
have radius vectors with the same norm, but in opposing directions
Then too. But not all photon characteristics are null; the outer radius
and the inner radius
may be greater than zero. Also consider the wavevector
which is found from the sum
But and
are out of phase, so
. And radius vectors are symmetrically opposed, so
. These two negative factors cancel each other such that
. Then we can express the wavevector as
The wavenumber is given by the norm of the wavevector, so
We can drop the subscript on because both phase-components have the same norm. And recall that
is the work required to build one of these phase-components. So in energetic terms, the photon’s wavenumber can be written as
Photon Type | π (m) |
---|---|
a gamma-ray | ![]() |
an X-ray | ![]() |
an ultraviolet photon | ![]() |
a visible photon | ![]() |
an infrared photon | ![]() |
a microwave | ![]() |
a radio-wave | ![]() |
Then the wavelength of a photon is
Finally recall that by definition the inner radius is constrained such that for all photons
Then if is a free particle where
and
is as small as possible, the wavelength will be
Photons are classified by wavelength as noted in accompanying table. A more general treatment considers that a photon’s wavelength may also depend on its surroundings. Then the symbol is used to indicate a wavelength where any such environmental effects are negligible. And next we mix photons with other substances to consider excited particles.