How accurately can our current technological tools measure the human bio-electromagnetic field emitted by a person? Or, to put it differently, does each person have a different electromagnetic field signature, and can we measure that with enough accuracy to tell two people apart by their frequencies?
[Physics] How accurately can we measure human electromagnetic fields
biophysicselectromagnetism
Best Answer
We can measure biomagnetism extremely precisely by using Superconducting QUantum Interference Devices (SQUIDs). These are sensitive to magnetic fluxes several orders of magnitude below the typical strength of biomagnetic effects. If you are familiar with quantum mechanics, then I strongly recommend reading the relevant sections of the Feynman Lectures, in which a heuristic, yet extremely clear, explanation of superconductivity, the Josephson effect and finally SQUIDs is presented.
Despite our capability to measure magnetic fluxes/fields with extreme precision, I think there are way too many variables to be able to distinguish people based on their magnetic fields. It is reasonable to assume that a person will not have an identical or even similar 'personal field' at different times, and disturbances from the environment will make it effectively impossible to measure regardless.