Light-particles seem like they exist for two reasons:
(1) when you detect things at high sensitivity, you get discrete events.
(2) Quantum fields have a thing called a number operator. When you "measure" it (whatever that means) you get an integer.
Now your language of "quantized packets of energy" comes from Einstein, who got his Nobel prize for noticing (1) in the form of the photoelectric effect. But that paper, though brilliant, was wrong. Classical fields (with quantum electrons) are enough to derive the photoelectric effect.
At first sight (2) seems to back Einstein up, since the number of photons seen on an (ideal) detector is pretty much the measured value of the number operator for the light beam.
But while that works in practice, it doesn't work in theory. The number operator is only really defined for monochromatic fields. It seems like you should be able to Fourier transform things until you had one for time-limited or space-limited situations. But I could never make that work.
(1) when you detect things at high sensitivity, you get discrete events.
(2) Quantum fields have a thing called a number operator. When you "measure" it (whatever that means) you get an integer.
Now your language of "quantized packets of energy" comes from Einstein, who got his Nobel prize for noticing (1) in the form of the photoelectric effect. But that paper, though brilliant, was wrong. Classical fields (with quantum electrons) are enough to derive the photoelectric effect.
At first sight (2) seems to back Einstein up, since the number of photons seen on an (ideal) detector is pretty much the measured value of the number operator for the light beam.
But while that works in practice, it doesn't work in theory. The number operator is only really defined for monochromatic fields. It seems like you should be able to Fourier transform things until you had one for time-limited or space-limited situations. But I could never make that work.