Quantum sensors are already here
Quantum technologies are all the hype now. Companies pop up left right and centre to sell you quantum computers, quantum simulations, simulations of quantum simulations, quantum encryption and quantum risk management.
The only caveat? Quantum computers don’t do anything useful yet! And while they one day will — with huge implications — there is another quantum technology which is already here, already useful, and might soon become a game-changer. Say welcome to quantum sensors.
In this sequence of stories, we will see what these sensors can be good for! Here in part 1, we will look at sensing magnetic fields and some ways quantum physics can make it faster, more precise and more accurate.
Quantum sensing of magnetic fields
Magnetic field is often the easiest thing for a quantum system to measure. This is basically because elementary particles have spin, which gives them a magnetic dipole moment. This manifests itself in variety of fundamental B-field-dependent effects.
The most common one for quantum sensors is the familiar Zeeman effect, where magnetic field causes one energy level of the quantum system to split into multiple ones, with energy gap proportional to the applied field. A quantum sensor will typically directly measure this splitting and extract the…
