Tiny magnet could help measure gravity on the quantum scale

A device that can measure the force of gravity on a particle weighing less than a grain of pollen could help us understand how Gravity works In the quantum world

Despite keeping you grounded, gravity is the weakest force we know of. Only massive objects, such as planets and stars, exert enough gravity to be easily measured. Do the same for Very small itemsThe small distance and mass of the quantum sphere is extremely difficult, partly because of the small size of the force, but also because larger objects in the vicinity can overwhelm the signal.

now Hendrick Albrecht At the University of Southampton in the UK and his colleagues, they have developed a new way to measure gravity on a small scale using a tiny neodymium magnet, weighing about 0.5 milligram, which is the same as Earth’s. emanates from the magnetic field to counteract gravity.

Small changes in the magnet’s magnetic field caused by the gravitational influence of nearby objects can then be converted into a measurement of the gravitational force. The entire object is cooled to near absolute zero and suspended in a system of springs to minimize external forces.

This probe can measure the gravity of objects weighing only a few micrograms. “You can increase the sensitivity and push gravity probes into a new regime,” Albrecht says.

He and his team found that with a 1 kg test mass orbiting nearby, they could measure a force on the particle of 30 Newtons. An Newton is a billionth of a billionth of a newton. One limitation is that the test mass must be moving at the correct speed to create gravitational resonance with the magnet, otherwise the force will not be strong enough to lift it.

The next step in the experiment would be to shrink the test mass like a magnetic particle, to test gravity while the particles are showing quantum effects like entanglement or superposition. That would be difficult, Albrecht says, because all the other parts of such a small-scale experiment would need to be incredibly precise, such as the exact distance between two particles. It may take at least a decade to reach this stage.

“The fact that they even tried this measurement is amazing to me,” says Julian Stirling, a UK-based engineer, due to the difficulty of separating other gravitational effects from the mass of their probe. Stirling says the researchers will need to figure out how to reduce the effect of gravity on the anti-vibrational system, since it appears to have had a small but significant effect on the levitated particle in the experiment.