# If you measured the electric field of a photon, would the value be constant in magnitude over time?

Because photons have varying probabilities of having angular momentum ℏ and -ℏ (depending on polarization), it doesn't seem like there's a true "linear" polarization. Instead with linearly polarized light you just have a 50/50 chance of getting either form of circularly polarized light.

I think this means that if you measured the orientation of a single photon's electric field, the value could be pointing in any direction, but would always be equal in magnitude. Repeating this process many times would then add these random distributions to the observed macroscopic value. Light's apparent sinusoidal variation in field intensity effectively results from summing many photon readings with different vectors; the magnitude of a photon's electric field is constant over time.

Is this interpretation correct? Does the photon have a constant electric field over time?

• The “electric field of a photon” is not a concept in physics. Photons are the quanta of the quantized electromagnetic field. Thinking that a photon has a field is a bit like thinking a wave has an ocean. It’s actually the other way around. Commented Jun 28, 2023 at 20:15
• Fair point. Would this be a better wording? "If you measured the oscillation in electric field at different time points, would you find that individual measurements of the oscillation remain constant in magnitude?" Commented Jun 28, 2023 at 20:35
• I think it’s legit to ask about measurements of the electromagnetic field in a one-photon quantum state. But you would not be measuring oscillations as such, because quantum fields do not have well-defined evolutions like classical fields do; you would be measuring field values at various places and times. There would be a lot of randomness, but the expectation values (averages of many measurements) would be predictable. I think quantities like $\langle \vec E \rangle$ and $\langle \vec{E}^2\rangle$ can be calculated in a one-photon state, and I think they are oscillatory. Commented Jun 28, 2023 at 21:18