Quantum spins move a centimetre scale object for the first time at OIST

[Mark94]

Researchers at the Okinawa Institute of Science and Technology have used quantum spin forces to move a centimetre scale object, ScienceAlert reports. Earlier experiments using spins only nudged individual atoms. This is a big jump in size. The paper appeared in Science Advances earlier in the week

The setup is clever. A centimetre sized graphite plate floats above a checkerboard of magnets. Hanging from it is a three millimetre diamond containing nitrogen vacancy centres, tiny defects whose electron spins can be controlled with light. Laser light set the spins, and a separate magnet turned those spin changes into movement

The whole assembly weighed about 128 milligrams and moved around 100 nanometres. That is eight to nine orders of magnitude more massive than current state of the art spin mechanical experiments. It is heavy enough to be affected by gravity, which opens up interesting possibilities. The motion itself is a classical response to a quantum effect

Jason Twamley summed it up neatly, saying the team has shown a large classical response from a small quantum effect. Daehee Kim said nitrogen vacancy diamonds are well understood and easy to control, which made them a good choice. The longer term hope is to put much larger objects into quantum superposition. Twamley said they need only another order of magnitude before they can finally observe effects they are aiming for

I love experiments like this because they probe the boundary between the quantum and everyday worlds. Why large objects behave classically is still one of the deep questions in physics. Getting a levitated object big enough to feel gravity under quantum control could help test ideas about quantum gravity. It is basic science at its most exciting

Could experiments like this help answer whether gravity is quantum? And where do you think the boundary between the quantum and classical worlds lies?

For The First Time Ever, Quantum Spins Shift a Centimeter-Scale Objectwww.sciencealert.com