[r58lf]

It's not a SQUID. There is new technology (quantum magnetometry) that measures slight shifts in molecular energy levels inside defects in synthetic diamonds. One of the google/alphabet spinouts from their quantum computing research is commercializing the technology (SandboxAQ).

The have a non contact MCG, like a EKG, but no electrical contacts. They can definitely "see" the heart beating from a few feet away.

SandboxAQ is also developing a navigation version. Put this sensitive magnetometer on a plane. You get very sensitive measurements of the local magnetic field. Once they have a region mapped, you can get exact positioning just from measuring magnetic fields.

You can extrapolate from SandboxAQ and get long range detection of a human heart. I don't know if it's real, but if so it's probably came out of that research effort.

[kuhsaft]

You are correct, it is not based on SQUID. But, I think SQUID is technically a class of quantum magnetometer? Quantum magnetometry is pretty vague, since most high-end magnetometers use some sort of quantum mechanics.

I think the term you're looking for is atomic-optical magnetometer. Someone posted a DARPA project (AMBIIENT), that uses one. What's special about the atomic-optical magnetometer, is that it measures the gradient directly. With SQUID, if you have two SQUIDs in a uniform magnetic field, you can't determine the vector of the field. But, with atomic-optical magnetometry you can.