Using small magnets to measure gravity at a quantum level

A device that can measure the force of gravity on particles lighter than a single grain of pollen could help us understand how gravity works in the quantum world.

Despite being stuck to the ground, gravity is the weakest force known to us. Only very large objects, such as planets and stars, generate enough gravity to be easily measured. Doing the same for a very small object at a fraction of the distance and mass in the quantum realm is also possible because the size of the force is so small, but a nearby larger object could overwhelm the signal. It is very difficult because there is

now hendrik ulbricht and colleagues at the University of Southampton in the UK have developed a new way to measure gravity on a small scale, using tiny neodymium magnets weighing about 0.5 milligrams that are suspended in a magnetic field that opposes Earth's gravity.

Small changes in the magnetic field of a magnet caused by the gravitational influence of nearby objects can be converted into a measure of gravity. The whole thing is cooled to near absolute zero and suspended on a spring system to minimize external forces.

This probe can measure the gravitational pull of objects weighing just a few micrograms. “We can increase the sensitivity and push the study of gravity into a new regime,” Ulbricht says.

He and his team found that a 1-kilogram test mass rotating nearby could measure a force of 30 atton-Newtons on a particle. An atnewton is one billionth of a newton. One limitation is that the test mass must be moving at a suitable velocity to cause gravitational resonance with the magnet. Otherwise, it will not be strong enough to pick up the force.

The next stage of the experiment will reduce the test mass to the same size as the magnetic particles so that gravity can be tested while the particles exhibit quantum effects such as entanglement and superposition. Ulbricht said this would be difficult because with such a small mass, all other parts of the experiment would need to be incredibly precise, such as the exact distance between the two particles. Masu. It may take at least 10 years to reach this stage.

“The fact that they even attempted this measurement is appalling to me,” he says. julian starlingis a UK-based engineer, as it is difficult to separate other gravitational effects from the exploration mass. Professor Starling said that in this experiment, the anti-vibration system appeared to have had a small but significant effect on airborne particles, so researchers need to find ways to minimize the gravitational effects of the anti-vibration system. It states that there is.